565 research outputs found
Growth, Condition, and Trophic Relations of Stocked Trout in Southern Appalachian Mountain Streams
Stream trout fisheries are among the most popular and valuable in the United States, but many are dependent on hatcheries to sustain fishing and harvest. Thus, understanding the ecology of hatchery‐reared trout stocked in natural environments is fundamental to management. We evaluated the growth, condition, and trophic relations of Brook Trout Salvelinus fontinalis, Brown Trout Salmo trutta, and Rainbow Trout Oncorhynchus mykiss that were stocked in southern Appalachian Mountain streams in western North Carolina. Stocked and wild (naturalized) trout were sampled over time (monthly; September 2012–June 2013) to compare condition and diet composition and to evaluate temporal dynamics of trophic position with stable isotope analysis. Relative weights (Wr) of stocked trout were inversely associated with their stream residence time but were consistently higher than those of wild trout. Weight loss of harvested stocked trout was similar among species and sizes, but fish stocked earlier lost more weight. Overall, 40% of 141 stomachs from stocked trout were empty compared to 15% of wild trout stomachs (N = 26). We identified a much higher rate of piscivory in wild trout (18 times that of stocked trout), and wild trout were 4.3 times more likely to consume gastropods relative to stocked trout. Hatchery‐reared trout were isotopically similar to co‐occurring wild fish for both δ13C and δ15N values but were less variable than wild trout. Differences in sulfur isotope ratios (δ34S) between wild and hatchery‐reared trout indicated that the diets of wild fish were enriched in δ34S relative to the diets of hatchery‐reared fish. Although hatcheryreared trout consumed prey items similar to those of wild fish, differences in consumption or behavior (e.g., reduced feeding) may have resulted in lower condition and negative growth. These findings provide critical insight on the trophic dynamics of stocked trout and may assist in developing and enhancing stream trout fisheries
Resonant Five-body Recombination in an Ultracold Gas of Bosonic Atoms
We combine theory and experiment to investigate five-body recombination in an
ultracold gas of atomic cesium at negative scattering length. A refined
theoretical model, in combination with extensive laboratory tunability of the
interatomic interactions, enables the five-body resonant recombination rate to
be calculated and measured. The position of the new observed recombination
feature agrees with a recent theoretical prediction and supports the prediction
of a family of universal cluster states at negative that are tied to an
Efimov trimer.Comment: 14 pages, 5 figure
Cardiac magnetic resonance assessment of central and peripheral vascular function in patients undergoing renal sympathetic denervation as predictor for blood pressure response
Background:
Most trials regarding catheter-based renal sympathetic denervation (RDN) describe a proportion of patients without blood pressure response. Recently, we were able to show arterial stiffness, measured by invasive pulse wave velocity (IPWV), seems to be an excellent predictor for blood pressure response. However, given the invasiveness, IPWV is less suitable as a selection criterion for patients undergoing RDN. Consequently, we aimed to investigate the value of cardiac magnetic resonance (CMR) based measures of arterial stiffness in predicting the outcome of RDN compared to IPWV as reference.
Methods:
Patients underwent CMR prior to RDN to assess ascending aortic distensibility (AAD), total arterial compliance (TAC), and systemic vascular resistance (SVR). In a second step, central aortic blood pressure was estimated from ascending aortic area change and flow sequences and used to re-calculate total arterial compliance (cTAC). Additionally, IPWV was acquired.
Results:
Thirty-two patients (24 responders and 8 non-responders) were available for analysis. AAD, TAC and cTAC were higher in responders, IPWV was higher in non-responders. SVR was not different between the groups. Patients with AAD, cTAC or TAC above median and IPWV below median had significantly better BP response. Receiver operating characteristic (ROC) curves predicting blood pressure response for IPWV, AAD, cTAC and TAC revealed areas under the curve of 0.849, 0.828, 0.776 and 0.753 (p = 0.004, 0.006, 0.021 and 0.035).
Conclusions:
Beyond IPWV, AAD, cTAC and TAC appear as useful outcome predictors for RDN in patients with hypertension. CMR-derived markers of arterial stiffness might serve as non-invasive selection criteria for RDN
SIRT1 decreases Lox-1-mediated foam cell formation in atherogenesis
Aims Endothelial activation, macrophage infiltration, and foam cell formation are pivotal steps in atherogenesis. Our aim in this study was to analyse the role of SIRT1, a class III deacetylase with important metabolic functions, in plaque macrophages and atherogenesis. Methods and results Using partial SIRT1 deletion in atherosclerotic mice, we demonstrate that SIRT1 protects against atherosclerosis by reducing macrophage foam cell formation. Peritoneal macrophages from heterozygous SIRT1 mice accumulate more oxidized low-density lipoprotein (oxLDL), thereby promoting foam cell formation. Bone marrow-restricted SIRT1 deletion confirmed that SIRT1 function in macrophages is sufficient to decrease atherogenesis. Moreover, we show that SIRT1 reduces the uptake of oxLDL by diminishing the expression of lectin-like oxLDL receptor-1 (Lox-1) via suppression of the NF-κB signalling pathway. Conclusion Our findings demonstrate protective effects of SIRT1 in atherogenesis and suggest pharmacological SIRT1 activation as a novel anti-atherosclerotic strategy by reducing macrophage foam cell formatio
SIRT1 decreases Lox-1-mediated foam cell formation in atherogenesis
Aims Endothelial activation, macrophage infiltration, and foam cell formation are pivotal steps in atherogenesis. Our aim in this study was to analyse the role of SIRT1, a class III deacetylase with important metabolic functions, in plaque macrophages and atherogenesis. Methods and results Using partial SIRT1 deletion in atherosclerotic mice, we demonstrate that SIRT1 protects against atherosclerosis by reducing macrophage foam cell formation. Peritoneal macrophages from heterozygous SIRT1 mice accumulate more oxidized low-density lipoprotein (oxLDL), thereby promoting foam cell formation. Bone marrow-restricted SIRT1 deletion confirmed that SIRT1 function in macrophages is sufficient to decrease atherogenesis. Moreover, we show that SIRT1 reduces the uptake of oxLDL by diminishing the expression of lectin-like oxLDL receptor-1 (Lox-1) via suppression of the NF-kappaB signalling pathway. Conclusion Our findings demonstrate protective effects of SIRT1 in atherogenesis and suggest pharmacological SIRT1 activation as a novel anti-atherosclerotic strategy by reducing macrophage foam cell formation
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A protocol for a randomised double-blind placebo-controlled feasibility study to determine whether the daily consumption of flavonoid-rich pure cocoa has the potential to reduce fatigue in people with relapsing and remitting multiple sclerosis (RRMS)
Background: Dietary interventions including consumption of flavonoids, plant compounds found in certain foods, may have the ability to improve fatigue. However, to date, no well-designed intervention studies assessing the role of flavonoid consumption for fatigue management in people with MS (pwMS) have been performed. The hypothesis is that the consumption of a flavonoid-rich pure cocoa beverage will reduce fatigue in pwMS. The aim of this study is to determine the feasibility and potential outcome of running a trial to evaluate this hypothesis. Methods: Using a randomised (1:1) double-blind placebo-controlled feasibility study, 40 men and women (20 in each trial arm) with a recent diagnosis (< 10 years) of relapsing and remitting MS (RRMS) and who are over 18 years of age will be recruited from neurology clinics and throughout the Thames Valley community. During a 6-week nutrition intervention period, participants will consume the cocoa beverage, high flavonoid or low flavonoid content, at breakfast daily. At baseline, demographic factors and disease-related factors will be assessed. Fatigue, activity and quality of life, in addition to other measures, will be taken at three visits (baseline, week 3 and week 6) in a university setting by a researcher blinded to group membership. Feasibility and fidelity will be assessed through recruitment and retention, adherence and a quantitative process evaluation at the end of the trial.We will describe demographic factors (age, gender, level of education) as well as disease-related factors (disease burden scores, length of time diagnosed with MS) and cognitive assessment, depression and quality of life and general physical activity in order to characterise participants and determine possible mediators to identify the processes by which the intervention may bring about change. Feasibility (recruitment, safety, feasibility of implementation of the intervention and evaluation, protocol adherence and data completion) and potential for benefit (estimates of effect size and variability) will be determined to inform future planned studies. Results will be presented using point estimates, 95% confidence intervals and p values. Primary statistical analysis will be on an intention-to-treat basis and will use the complete case data set. Discussion: We propose that a flavonoid-enriched cocoa beverage for the management of fatigue will be well received by participants. Further, if it is implemented early in the disease course of people diagnosed with RRMS, it will improve mobility and functioning by modifying fatigue. Trial registration: Registered with ISRCTN Registry. Trial registration No: ISRCTN69897291; Date April 2016
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Monounsaturated fats and immune function
Animal studies suggest that olive oil is capable of modulating functions of cells of the immune system in a manner similar to, albeit weaker than, fish oils. There is some evidence that the effects of olive oil on immune function in animal studies are due to oleic acid rather than to trace elements or antioxidants. Importantly, several studies have demonstrated effects of oleic acid-containing diets on in vivo immune responses. In contrast, consumption of a monounsaturated fatty acid (MUFA)-rich diet by humans does not appear to bring about a general suppression of immune cell functions. The effects of this diet in humans are limited to decreasing aspects of adhesion of peripheral blood mononuclear cells, although there are trends towards decreases in natural killer cell activity and proliferation. The lack of a clear effect of MUFA in humans may be attributable to the higher level of monounsaturated fat used in the animal studies, although it is ultimately of importance to examine the effects of intakes which are in no way extreme. The effects of MUFA on adhesion molecules are potentially important, since these molecules appear to have a role in the pathology of a number of diseases involving the immune system. This area clearly deserves further exploration
Utility of Atherosclerosis Imaging in the Evaluation of High-Density Lipoprotein–Raising Therapies
Decreased level of high density-lipoprotein cholesterol (HDL-C) is a rigorous predictor for future cardiovascular events. Much effort is being made to develop HDL-C–raising pharmacotherapies in the attempt to avert the pandemic of atherosclerotic disease. Important properties by which HDL-C–raising compounds are effective involve improvement of cholesterol uptake from macrophages in plaque for transport back to the liver, improvement of endothelial function, and anti-inflammatory effects. Vascular imaging can aid in the determination which HDL-C–raising compounds are effective. Ultrasound and MRI have proved suitable for assessment of structural changes of the vessel wall. Ultrasound can also be used or assessment of endothelial function. 18F-fluordeoxyglucose positron emission tomography has opened up the possibility to assess vessel wall inflammation. In this article we discuss these various imaging techniques and how they can assess efficacy as well as provide pathophysiologic information on the mechanism of action of novel HDL-C–raising drugs
Flexibility of a biotinylated ligand in artificial metalloenzymes based on streptavidin—an insight from molecular dynamics simulations with classical and ab initio force fields
In the field of enzymatic catalysis, creating activity from a non catalytic scaffold is a daunting task. Introduction of a catalytically active moiety within a protein scaffold offers an attractive means for the creation of artificial metalloenzymes. With this goal in mind, introduction of a biotinylated d6-piano-stool complex within streptavidin (SAV) affords enantioselective artificial transfer-hydrogenases for the reduction of prochiral ketones. Based on an X-ray crystal structure of a highly selective hybrid catalyst, displaying significant disorder around the biotinylated catalyst [η6-(p-cymene)Ru(Biot-p-L)Cl], we report on molecular dynamics simulations to shed light on the protein–cofactor interactions and contacts. The results of these simulations with classical force field indicate that the SAV-biotin and SAV-catalyst complexes are more stable than ligand-free SAV. The point mutations introduced did not affect significantly the overall behavior of SAV and, unexpectedly, the P64G substitution did not provide additional flexibility to the protein scaffold. The metal-cofactor proved to be conformationally flexible, and the S112K or P64G mutants proved to enhance this effect in the most pronounced way. The network of intermolecular hydrogen bonds is efficient at stabilizing the position of biotin, but much less at fixing the conformation of an extended biotinylated ligand. This leads to a relative conformational freedom of the metal-cofactor, and a poorly localized catalytic metal moiety. MD calculations with ab initio potential function suggest that the hydrogen bonds alone are not sufficient factors for full stabilization of the biotin. The hydrophobic biotin-binding pocket (and generally protein scaffold) maintains the hydrogen bonds between biotin and protein
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