Associate Professor Thomas WALCZYK



Dipl. Chem., University of Regensburg, 1990, Germany; Ph.D., University of Regensburg, Germany, 1994; Postdoctoral, 1994-1997, and Lecturer, ETH Zurich, Switzerland, 1997-2007.

Contact Information

Office: S13-05-11
Tel: (65)-6516-7986 | Fax: (65)-6779-1691
Email: chmwtr@nus.edu.sg | Personal webpage


 

Research Interests

Research at our lab is directed towards a better understanding of mineral and trace element metabolism in humans and their role in health and disease with a special focus on iron and calcium. Specific foci are:

  • Factors affecting absorption, utilization and excretion of essential elements by the human body
  • Development and application of stable isotope techniques for element tracing in animal and human studies
  • Exploration of natural isotope signatures in the human body for essential elements
  • Inorganic trace analysis and elemental speciation analysis by isotope dilution mass spectrometry

 

Research Highlight

Iron deposits in brain are a hallmark of several neurodegenerative disorders including Parkinson’s and Alzheimer’s Disease. Earlier short-term experiments in rodents using radiotracers showed that uptake of injected iron by the healthy brain is only marginal after closure of the blood brain barrier early in life (< 0.001% of dose). In a series of rat studies we pioneered stable isotope tracing of iron from diet to brain in the first ever long-term in vivo experiment involving continuous tracer feeding. In agreement with earlier studies we found that only a minor fraction of administered iron entered the brain. However, due to the low concentration of iron in brain, this fraction amounted to ca. 10% of brain iron which challenges current textbook knowledge. In a second experiment we could show that iron influx exceeds iron efflux in the long-term and that iron accumulation in brain over lifetime is apparently inevitable.
Ref: Chen, J.; Singh, N. N.; Tay, H.; Walczyk, T., Imbalance of iron influx and efflux causes brain iron accumulation over time in the healthy adult rat. Metallomics 2014, 6, 1417-1426; Chen, J.; Shinavas, S.; Singh, N. N.; Ong, W. Y.; Walczyk, T., Stable iron isotope tracing reveals significant brain iron uptake in adult rats. Metallomics 2013, 5, 167-173.

 

Teaching Contributions

  • CM3261 Environmental Chemistry
  • CM4241 Trace Analysis

 

Representative Publications 

  • Hotz, K.; Walczyk, T. Natural Iron Isotopic Composition of Blood is an Indicator of Dietary Iron Absorption Efficiency in Humans. J. Biol. Inorg. Chem. 2013, 18, 1-7.
  • Chew, G.; Walczyk, T. Measurement of Isotope Abundance Variations in Nature by Gravimetric Spiking Isotope Dilution Analysis (GS-IDA). Anal. Chem. 2013, 85, 3667-3673.
  • Hotz, K.; Augsburger, H.; Walczyk, T. Isotopic Signatures of Iron in Body Tissues as a Potential Biomarker for Iron Metabolism. J. Anal. Atom. Spectrom. 2011, 26, 1347-1353.
  • Bullen, T. D.; Walczyk, T. Environmental and Biomedical Applications of Natural Metal Stable Isotope Variations. Elements 2009, 5, 381-385.
  • Hoppler, M.; Zeder, C.; Walczyk, T. Quantification of Ferritin-Bound Iron in Plant Samples by Isotope Tagging and Species-Specific Isotope Dilution Mass Spectrometry. Anal. Chem. 2009, 81, 7368-7372.
  • Denk, E.; Hillegonds, D.; Vogel, J.; Synal, A.; Geppert, C.; Wendt, K.; Fattinger, K.; Hennessy, C.; Berglund, M.; Hurrell, R. F.; Walczyk, T. Labeling the Human Skeleton with Ca-41 to Assess Changes in Bone Calcium Metabolism. Anal. Bioanal. Chem. 2006, 386, 1587-1602. [ABC Best Paper Award 2007].
  • Krayenbuehl, P. A.; Walczyk, T.; Schoenberg, R.; von Blanckenburg, F.; Schulthess, G. Hereditary Hemochromatosis is Reflected in the Iron Isotope Composition of Blood. Blood 2005, 105, 3812-3816.