The impact of blood on liver metabolite profiling – a combined metabolomic and proteomic approach

Metabolomics has entered the well‐established omic sciences as it is an indispensable information resource to achieve a global picture of biological systems. The aim of the present study was to estimate the influence of blood removal from mice liver as part of sample preparation for metabolomic and proteomic studies. For this purpose, perfused mice liver tissue (i.e. with blood removed) and unperfused mice liver tissue (i.e. containing blood) were compared by two‐dimensional gas chromatography time of flight mass spectrometry (GC × GC‐TOFMS) for the metabolomic part, and by liquid chromatography tandem mass spectrometry (LC‐MS/MS) for the proteomic part. Our data showed significant differences between the unperfused and perfused liver tissue samples. Furthermore, we also observed an overlap of blood and tissue metabolite profiles in our data, suggesting that the perfusion of liver tissue prior to analysis is beneficial for an accurate metabolic profile of this organ. Copyright © 2013 John Wiley & Sons, Ltd.     

Tracking Defects and Microstructural Heterogeneities in Meso-Scale Tensile Specimens Excised from Additively Manufactured Parts

Experimental Mechanics - The commercialization of additive manufacturing (AM) is underway in the aerospace and biomedical device industries [1, 2]. However, most metal parts produced by AM are...     

Two analytical solutions for a model of pulsed arterial spin labeling with randomized blood arrival times

A fairly general theoretical model for pulsed arterial spin labeling perfusion methods has been available for some time but analytical solutions were derived for only a small number of arterial blood input functions. These mostly assumed a sudden and simultaneous arrival of the tagged blood into the imaged region. More general cases had to be handled numerically. We present analytical solutions for two more realistic arterial input functions. They both allow the arrival times of the molecules of tagged arterial blood to be statistically distributed. We consider cases of (1) a uniform distribution on a finite time interval and (2) a normal distribution characterized by its mean and standard deviation. These models are physiologically meaningful because the statistical nature of the arrival times reflects the distribution of velocities and path lengths that the blood water molecules undertake from the tagging region to the imaged region. The model parameters can be estimated from the measured dependency of the perfusion signal on the tag inversion time.     

Moses: multiple oversampled slabs EPI sequence

A new technique is proposed which combines the advantages of phase encoded and multi-slice echo planar imaging (EPI) methods. Its principle is to interleave multiple phase encoded EPI slabs. This approach can provide a larger spatial coverage than multi-slice EPI for the same signal to noise ratio and total imaging time and a shorter minimum imaging time than 3D EPI for the same coverage and repetition time. Other advantages include availability of the steady state image contrasts and potentially lower acoustic noise and RF specific absorption rate compared to the standard multi-slice EPI. A full discussion of its potential as well as in vivo results at 1.5 and 3 Tesla are presented in this paper.