216 research outputs found
All cholesterol-lowering interventions are expected to reduce stroke: Confirmatory data from IMPROVE-IT
No full textAbstractThe relationship of cholesterol with stroke is much less clear than its relationship with myocardial infarction, thus confounding the interpretation of results with cholesterol-lowering trials (Di Napoli et al., 2002) [1], (De Caterina et al., 2010) [2]). IMPROVE-IT data ((Cannon et al. 2015) [3]), showing a 13.3% reduction in total cholesterol at one year in association with a hazard ratio (HR) of 0.i86 for total stroke during the trial, are very closely aligned with the relative risk of 0.90 predicted based on the totality of lipid lowering interventions ((De Caterina et al., 2016) [4]). We here provide the data from the original trials used to construct this meta-analysis, with the now added additional data from IMPROVE-IT, well-fitting the previously found meta-regression line.These data are important to predict stroke outcomes in currently ongoing trials now testing PCSK9 or cholesterol ester transfer protein inhibitors
All cholesterol-lowering interventions are expected to reduce stroke: Confirmatory data from IMPROVE-IT
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Cholesterol Lowering and Stroke: No Longer Room for Pleiotropic Effects of Statins - Confirmation from PCSK9 Inhibitor Studies
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Orientation, distribution, and deformation of inertial flexible fibers in turbulent channel flow
No full textIn this paper, we investigate the dynamics of flexible fibers in turbulent channel flow. Fibers are longer than the Kolmogorov length scale of the carrier flow, and their velocity relative to the surrounding fluid is non-negligible. Our aim is to examine the effect of local shear and turbulence anisotropy on the translational and rotational behavior of the fibers, considering different elongation (parameterized by the aspect ratio, λ) and inertia (parameterized by the Stokes number, St). To these aims, we use a Eulerian–Lagrangian approach based on direct numerical simulation of turbulence in the dilute regime. Fibers are modeled as chains of sub-Kolmogorov rods (referred to as elements hereinafter) connected through ball-and-socket joints that enable bending and twisting under the action of the local fluid velocity gradients. Velocity, orientation, and concentration statistics, extracted from simulations at shear Reynolds number Reτ = 150 (based on the channel half height), are presented to give insights into the complex fiber–turbulence interactions that arise when non-sphericity and deformability add to inertial bias. These statistical observables are examined at varying aspect ratios (namely λ_r = l_r /a = 2 and 5, with l_r the semi-length of each rod-like element r composing the fiber and a its cross-sectional radius) and varying fiber inertia (considering values of the element Stokes number, St_r = 1, 5, 30). To highlight the effect of flexibility, statistics are compared with those obtained for fibers of equal mass that translate and rotate as rigid bodies relative to the surrounding fluid. Flexible fibers exhibit a stronger tendency to accumulate in the very-near-wall region, where they appear to be trapped by the same inertia-driven mechanisms that govern the preferential concentration of spherical particles and rigid fibers in bounded flows. In such region, the bending of flexible fibers increases as inertia decreases, and fiber deformation appears to be controlled by mean shear and turbulent Reynolds stresses. Preferential segregation
into low-speed streaks and preferential orientation in the mean flow direction is also observed
Cardiovascular risk changes after lipid lowering modifications: are they predictable?
No full textChanges in cardiovascular risk after lipid lowering medications are generally expressed as relative risk reduction (RRR). Comparison of the eight major studies published in this last decade indicates that the RRRs ranged from a minimum (19%) for the LRC Study with cholestyramine, to maximal values of 34-37% for studies such as the HHS, 4S and AFCAPS/TexCAPS. These RRRs were barely related to the drugs' effects on major lipid parameters, e.g. LDL cholesterol. Instead, by using the absolute risk reduction (ARRs), easily calculated by subtracting the percentage end points for the drug treated from these values of the placebo group in all studies, a wide range of values was found, also adding to the series a non pharmacological study such as the Program on the Surgical Control of the Hyperlipidemias (POSCH) trial. Calculated ARRs were directly correlated to the baseline cardiovascular (CV) risk in all studies, thus allowing an easy prediction of a drug's effect in the selected population. Drugs with different mechanisms (statins, fibrates and resins) all fitted into this correlation nomogram. These findings clearly indicate that the CV effects of lipid changes, such as LDL cholesterol and triglyceride reduction or HDL rises, are in the same direction, and can be well predicted. The similar, almost identical behavior of drugs affecting LDL cholesterolemia to a different degree or not at all, indicates that novel approaches should be sought to improve risk reduction and that individual therapy should be ideally pursued, rather than a 'one drug' approach. (C) 2000 Elsevier Science Ireland Ltd
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