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Quantitative Kernspintomographie: Ein paramagnetisches Gadolinium ‐ beladenes Liposom für MRI ‐ Studien der Aktivität der Matrixmetalloproteinase ‐ 2 (MMP ‐ 2) wird beschrieben. Die Messung beruht auf dem Verhältnis R2p/R1p zwischen den transversalen und longitudinalen paramagnetischen Beiträgen der Relaxationsgeschwindigkeit des Wasserprotons. Die Methode ist unabhängig von der Gesamtkonzentration an Gadolinium. [ABSTRACT FROM AUTHOR]

Parametric MRI: A paramagnetic gadolinium‐loaded liposome for the MRI assessment of the activity of matrix metalloproteinase‐2 (MMP‐2) is described. The assessment relies on a procedure that involves the ratio R2p/R1p between the transverse and longitudinal paramagnetic contributions to the water proton relaxation rate. This method is independent of the total gadolinium concentration. [ABSTRACT FROM AUTHOR]

Abstract: Scalar coupling relaxation, which is usually only associated with closely resonant nuclei (e.g., 79Br–13C), can be a very effective relaxation mechanism. While working on hyperpolarized [5-13C]glutamine, fast liquid-state polarization decay during transfer to the MRI scanner was observed. This behavior could hypothetically be explained by substantial T 1 shortening due to a scalar coupling contribution (type II) to the relaxation caused by the fast-relaxing quadrupolar 14N adjacent to the 13C nucleus in the amide group. This contribution is only effective in low magnetic fields (i.e., less than 800μT) and prevents the use of molecules bearing the 13C-amide group as hyperpolarized MRS/MRI probes. In the present work, this hypothesis is explored both theoretically and experimentally. The results show that high hyperpolarization levels can be retained using either a 15N-labeled amide or by applying a magnetic field during transfer of the sample from the polarizer to the MRI scanner. [Copyright &y& Elsevier]

In the metabolism of acetate several enzymes are involved, which play an important role in free fatty acid oxidation. Fatty acid metabolism is altered in diabetes patients and therefore acetate might serve as a marker for pathological changes in the fuel selection of cells, as these changes occur in diabetes patients. Acetylcarnitine is a metabolic product of acetate, which enables its transport into the mitochondria for energy production. This study investigates whether the ratio of acetylcarnitine to acetate, measured by noninvasive hyperpolarized [1-13C]acetate magnetic resonance spectroscopy, could serve as a marker for myocardial, hepatic, and renal metabolic changes in rats with Streptozotocin ( STZ)-induced diabetes in vivo. We demonstrate that the conversion of acetate to acetylcarnitine could be detected and quantified in all three organs of interest. More interestingly, we found that the hyperpolarized acetylcarnitine to acetate ratio was independent of blood glucose levels and prolonged hyperglycemia following diabetes induction in a type-1 diabetes model. [ABSTRACT FROM AUTHOR]

Newfluorinated, arylsulfone-based matrix metalloproteinase (MMP)inhibitors containing carboxylate as the zinc binding group were synthesizedas radiotracers for positron emission tomography. Inhibitors werecharacterized by Kifor MMP-2 in the nanomolarrange and by a fair selectivity for MMP-2/9/12/13 over MMP-1/3/14.Two of these compounds were obtained in the 18F-radiolabeledform, with radiochemical purity and yield suitable for preliminarystudies in mice xenografted with a human U-87 MG glioblastoma. Targetdensity in xenografts was assessed by Western blot, yielding Bmax/Kd= 14. Thebiodistribution of the tracer was dominated by liver uptake and hepatobiliaryclearance. Tumor uptake of 18F-labeled MMP inhibitors wasabout 30% that of [18F]fluorodeoxyglucose. Accumulationof radioactivity within the tumor periphery colocalized with MMP-2activity (evaluated by in situ zimography). However, specific tumoruptake accounted for only 18% of total uptake. The aspecific uptakewas ascribed to the high binding affinity between the radiotracerand serum albumin. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Carnitine Acyltransferases and Their Influence on CoA pools in Health and Disease" by V. A. Zammit and colleagues in the 2016 issue.