Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: April 6, 2000
Publication Date: N/A
Interpretive Summary: This review summarizes the use of stable and radioactive isotopes of manganese, molybdenum and chromium in human experiments. The review gives a brief summary of the chemistry and biochemistry of each element, and the different forms of tracers that have been used in past human studies. The review discusses methodological problems in administering and detecting the isotopes and the interpretation of data from such studies. Pertinent human experiments are summarized and discussed. The information will be of value to other researchers for experiment planning, method development and data analysis.
Technical Abstract: Isotopes of manganese (Mn), chromium (Cr) and molybdenum (Mo) have been used as tracers in many biochemical, physiological and nutritional studies. Manganese has only one stable isotope, and thus only radioactive isotopes are available for use as tracers. Radioactive Mn has been used to study the nutritional essentiality, as well as the potential toxicity of Mn. Human studies with radioactive Mn require access to a sensitive whole-body counter and various mathematical models of whole-body radioactivity has been used to estimate absorption and human studies. Tracers have been used as biomarkers to estimate physiological pools (e.g. blood volume) and flow rates (e.g. movement of chyme through the digestive tract) as well as to study chromium nutrition and biochemistry. Radioactive tracers of Mo are primarily encountered in humans as a contamination product of technetium (Tc)/Mo generators. Radioactive Tc is often used as a probe to label pharmaceuticals, and generation of Tc results in the formation of a small amount of radioactive Mo. Stable isotopes of Mo have been used to study human Mo nutrition and biochemistry.