Time course of eosinophilic myocarditis visualized by CMR

We report the diagnostic potential of cardiovascular magnetic resonance (CMR) to visualize the time course of eosinophilic myocarditis upon successful treatment. A 50-year-old man was admitted with a progressive heart failure. Endomyocardial biopsies were taken from the left ventricle because of a white blood cell count of 17000/mm3 with 41% eosinophils. Histological evaluation revealed endomyocardial eosinophilic infiltration and areas of myocyte necrosis. The patient was diagnosed with hypereosinophilic myocarditis due to idiopathic hypereosinophilic syndrome. CMR-studies at presentation and a follow-up study 3 weeks later showed diffuse subendocardial LGE in the whole left ventricle. Upon treatment with steroids, CMR-studies revealed marked reduction of subendocardial LGE after 3 months in parallel with further clinical improvement. This case therefore highlights the clinical importance of CMR to visualize the extent of endomyocardial involvement in the diagnosis and treatment of eosinophilic myocarditis

Simulation of fluid-solid coexistence in finite volumes: A method to study the properties of wall-attached crystalline nuclei

The Asakura-Oosawa model for colloid-polymer mixtures is studied by Monte Carlo simulations at densities inside the two-phase coexistence region of fluid and solid. Choosing a geometry where the system is confined between two flat walls, and a wall-colloid potential that leads to incomplete wetting of the crystal at the wall, conditions can be created where a single nanoscopic wall-attached crystalline cluster coexists with fluid in the remainder of the simulation box. Following related ideas that have been useful to study heterogeneous nucleation of liquid droplets at the vapor-liquid coexistence, we estimate the contact angles from observations of the crystalline clusters in thermal equilibrium. We find fair agreement with a prediction based on Young's equation, using estimates of interface and wall tension from the study of flat surfaces. It is shown that the pressure versus density curve of the finite system exhibits a loop, but the pressure maximum signifies the "droplet evaporation-condensation" transition and thus has nothing in common with a van der Waals-like loop. Preparing systems where the packing fraction is deep inside the two-phase coexistence region, the system spontaneously forms a "slab state", with two wall-attached crystalline domains separated by (flat) interfaces from liquid in full equilibrium with the crystal in between; analysis of such states allows a precise estimation of the bulk equilibrium properties at phase coexistence

Hard sphere fluids confined between soft repulsive walls: A comparative study using Monte Carlo and density functional methods

Hard-sphere fluids confined between parallel plates a distance $D$ apart are studied for a wide range of packing fractions, including also the onset of crystallization, applying Monte Carlo simulation techniques and density functional theory. The walls repel the hard spheres (of diameter $\sigma$) with a Weeks-Chandler-Andersen (WCA) potential $V_{WCA}(z) = 4 \epsilon [(\sigma_w/z)^{12}-(\sigma_w/z)^6 + 1/4]$, with range $\sigma_w = \sigma/2$. We vary the strength $\epsilon$ over a wide range and the case of simple hard walls is also treated for comparison. By the variation of $\epsilon$ one can change both the surface excess packing fraction and the wall-fluid $(\gamma_{wf})$ and wall-crystal $(\gamma_{wc})$ surface free energies. Several different methods to extract $\gamma_{wf}$ and $\gamma_{wc}$ from Monte Carlo (MC) simulations are implemented, and their accuracy and efficiency is comparatively discussed. The density functional theory (DFT) using Fundamental Measure functionals is found to be quantitatively accurate over a wide range of packing fractions; small deviations between DFT and MC near the fluid to crystal transition need to be studied further. Our results on density profiles near soft walls could be useful to interpret corresponding experiments with suitable colloidal dispersions.Comment: 23 pages, 7 ps, eps figure

Methods to Compute Pressure and Wall Tension in Fluids containing Hard Particles

Colloidal systems are often modelled as fluids of hard particles (possibly with an additional soft attraction, e.g. caused by polymers also contained in the suspension). in simulations of such systems, the virial theorem cannot be straightforwardly applied to obtain the components of the pressure tensor. In systems confined by walls, it is hence also not straightforward to extract the excess energy due to the wall (the "wall tension") from the pressure tensor anisotropy. A comparative evaluation of several methods to circumvent this problem is presented, using as examples fluids of hard spheres and the Asakura-Oosawa model of colloid-polymer mixtures with a size ratio $q=0.15$ (for which the effect of the polymers can be integrated out to yield an effective attractive potential between the colloids). Factors limiting the accuracy of the various methods are carefully discussed, and controlling these factors very good mutual agreement between the various methods is found.Comment: 15 pages, 6 figure

NFATc1 affects mouse splenic B cell function by controlling the calcineurin–NFAT signaling network

Mouse B cells lacking NFATc1 exhibit defective proliferation, survival, isotype class switching, cytokine production, and T cell help

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data