Johannes H. G. M. van Beek

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MOTIVATION Quantitative determination of metabolic fluxes in single tissue biopsies is difficult. We report a novel analysis approach and software package for in vivo flux quantification using stable isotope labeling. RESULTS We developed a protocol based on brief, timed infusion of (13)C isotope-enriched substrates for the tricarboxylic acid (TCA) cycle(More)
The aerobic energy metabolism of cardiac muscle cells is of major importance for the contractile function of the heart. Because energy metabolism is very heterogeneously distributed in heart tissue, especially during coronary disease, a method to quantify metabolic fluxes in small tissue samples is desirable. Taking tissue biopsies after infusion of(More)
In this study the function of the two isoforms of creatine kinase (CK; EC 2.7.3.2) in myocardium is investigated. The 'phosphocreatine shuttle' hypothesis states that mitochondrial and cytosolic CK plays a pivotal role in the transport of high-energy phosphate (HEP) groups from mitochondria to myofibrils in contracting muscle. Temporal buffering of changes(More)
The human physiological system is stressed to its limits during endurance sports competition events. We describe a whole body computational model for energy conversion BLOCKINduring BLOCKINbicycle BLOCKINracing. BLOCKINAbout BLOCKIN23 BLOCKINper BLOCKINcent BLOCKINof BLOCKINthe BLOCKINmetabolic BLOCKINenergy BLOCKINis BLOCKINused BLOCKINfor muscle work, the(More)
We have designed a method to encode properties related to the electron densities of molecules (calculated (1)H and (13)C NMR shifts and atomic partial charges) in molecular fingerprints (EDprints). EDprints was evaluated in terms of their retrospective virtual screening accuracy against the Directory of Useful Decoys (DUD) and compared to the established(More)
The representation of biochemical knowledge in terms of fluxes (transformation rates) in a metabolic network is often a crucial step in the development of new drugs and efficient bioreactors. Mass spectroscopy (MS) and nuclear magnetic resonance spectroscopy (NMRS) in combination with 13 C labeled substrates are experimental techniques resulting in data(More)
At rest, myocardial perfusion is reasonably well matched to regional metabolic demand, although both are heterogeneously distributed. Nonuniform regional metabolic vulnerability during coronary stenosis would help to explain nonuniform necrosis during myocardial infarction. We investigated two questions: (1) does the metabolism-perfusion correlation(More)
It used to be difficult to quantitate aerobic metabolic flux in mammalian tissue samples, especially in the multiple samples necessary to reveal spatial heterogeneity of energy turnover. Here we discuss a strategy to infuse carbon-13 labeled substrates for aerobic metabolism and obtain myocardial tissue samples after 5-7 min, before the isotopic steady(More)
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