Probing metabolite diffusion at ultra-short time scales in the mouse brain using optimized oscillating gradients and “short”-echo-time diffusion-weighted MRS

It is generally agreed that both the landfill option, or the civil techniques option for the final disposal of contaminated harbour sludge involves the isolation of the sludge from the environment. For short time scales, engineered barriers such as a bentonite screen, plastic sheets, pumping strategies etc. can be used. However for long time scales the effectiveness of such measures cannot be counted upon. It is thus necessary to be able to predict the long term environmenttal spread of contaminants from a mature landfill. A model is presented that considers diffusion and adsorption in the landfill site and convection and adsorption in the underlaying aquifer. From a parameter analysis starting form practical values it is shown that the adsorption behaviour and the molecular diffusion coefficient of the sludge, are the key parameters involved in the near field. The dilution effects of the far field migration patterns are also illustrated.

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Impact of tumor-parenchyma biomechanics on liver metastatic progression: a multi-model approach

Scientific Reports ◽

10.1038/s41598-020-78780-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Yafei Wang ◽

Erik Brodin ◽

Kenichiro Nishii ◽

Hermann B. Frieboes ◽

Shannon M. Mumenthaler ◽

...

Keyword(s):

Time Scales ◽

Constitutive Relations ◽

Elastic Tissue ◽

Metastatic Progression ◽

Patient Death ◽

Metastatic Growth ◽

Tumor Parenchyma ◽

Short Time ◽

Model Approach

AbstractColorectal cancer and other cancers often metastasize to the liver in later stages of the disease, contributing significantly to patient death. While the biomechanical properties of the liver parenchyma (normal liver tissue) are known to affect tumor cell behavior in primary and metastatic tumors, the role of these properties in driving or inhibiting metastatic inception remains poorly understood, as are the longer-term multicellular dynamics. This study adopts a multi-model approach to study the dynamics of tumor-parenchyma biomechanical interactions during metastatic seeding and growth. We employ a detailed poroviscoelastic model of a liver lobule to study how micrometastases disrupt flow and pressure on short time scales. Results from short-time simulations in detailed single hepatic lobules motivate constitutive relations and biological hypotheses for a minimal agent-based model of metastatic growth in centimeter-scale tissue over months-long time scales. After a parameter space investigation, we find that the balance of basic tumor-parenchyma biomechanical interactions on shorter time scales (adhesion, repulsion, and elastic tissue deformation over minutes) and longer time scales (plastic tissue relaxation over hours) can explain a broad range of behaviors of micrometastases, without the need for complex molecular-scale signaling. These interactions may arrest the growth of micrometastases in a dormant state and prevent newly arriving cancer cells from establishing successful metastatic foci. Moreover, the simulations indicate ways in which dormant tumors could “reawaken” after changes in parenchymal tissue mechanical properties, as may arise during aging or following acute liver illness or injury. We conclude that the proposed modeling approach yields insight into the role of tumor-parenchyma biomechanics in promoting liver metastatic growth, and advances the longer term goal of identifying conditions to clinically arrest and reverse the course of late-stage cancer.

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Ultra-short echo-time MRI detects changes in bone mineralization and water content in OVX rat bone in response to alendronate treatment

Bone ◽

10.1016/j.bone.2010.01.372 ◽

2010 ◽

Vol 46 (5) ◽

pp. 1391-1399 ◽

Cited By ~ 41

Author(s):

S. Anumula ◽

S.L. Wehrli ◽

J. Magland ◽

A.C. Wright ◽

F.W. Wehrli

Keyword(s):

Water Content ◽

Bone Mineralization ◽

Alendronate Treatment ◽

Echo Time ◽

Short Echo Time ◽

Rat Bone

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Subclavian MR Arteriography: Reduction of Susceptibility Artifact with Short Echo Time and Dilute Gadopentetate Dimeglumine

Radiology ◽

10.1148/radiology.217.2.r00oc37581 ◽

2000 ◽

Vol 217 (2) ◽

pp. 581-586 ◽

Cited By ~ 38

Author(s):

Mohammed A. Neimatallah ◽

Thomas L. Chenevert ◽

Ruth C. Carlos ◽

Frank J. Londy ◽

Qian Dong ◽

...

Keyword(s):

Gadopentetate Dimeglumine ◽

Susceptibility Artifact ◽

Echo Time ◽

Short Echo Time

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Variations in the depositional fluxes of cosmogenic beryllium on short time scales

Atmospheric Environment ◽

10.1016/j.atmosenv.2011.03.005 ◽

2011 ◽

Vol 45 (17) ◽

pp. 2836-2841 ◽

Cited By ~ 6

Author(s):

M. Mann ◽

J. Beer ◽

F. Steinhilber ◽

J.A. Abreu ◽

M. Christl ◽

...

Keyword(s):

Time Scales ◽

Short Time

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Assessment of Metabolic Fluxes in the Mouse Brain in Vivo Using 1H-[13C] NMR Spectroscopy at 14.1 Tesla

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.2014.251 ◽

2015 ◽

Vol 35 (5) ◽

pp. 759-765 ◽

Cited By ~ 15

Author(s):

Lijing Xin ◽

Bernard Lanz ◽

gxia Lei ◽

Rolf Gruetter

Keyword(s):

Mouse Models ◽

Mouse Brain ◽

Conversion Rate ◽

Tca Cycle ◽

Compartment Model ◽

13C Nmr Spectroscopy ◽

Resonance Spectroscopy ◽

Metabolic Fluxes ◽

Short Echo Time

13C magnetic resonance spectroscopy (MRS) combined with the administration of 13C labeled substrates uniquely allows to measure metabolic fluxes in vivo in the brain of humans and rats. The extension to mouse models may provide exclusive prospect for the investigation of models of human diseases. In the present study, the short-echo-time (TE) full-sensitivity 1H-[13C] MRS sequence combined with high magnetic field (14.1 T) and infusion of [U-13C6] glucose was used to enhance the experimental sensitivity in vivo in the mouse brain and the 13C turnover curves of glutamate C4, glutamine C4, glutamate+glutamine C3, aspartate C2, lactate C3, alanine C3, γ-aminobutyric acid C2, C3 and C4 were obtained. A one-compartment model was used to fit 13C turnover curves and resulted in values of metabolic fluxes including the tricarboxylic acid (TCA) cycle flux VTCA (1.05 ± 0.04 μmol/g per minute), the exchange flux between 2-oxoglutarate and glutamate Vx (0.48 ± 0.02 μmol/g per minute), the glutamate-glutamine exchange rate Vgln (0.20 ± 0.02 μmol/g per minute), the pyruvate dilution factor Kdil (0.82 ± 0.01), and the ratio for the lactate conversion rate and the alanine conversion rate VLac/ VAla (10 ± 2). This study opens the prospect of studying transgenic mouse models of brain pathologies.

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