Tracers, biological

Be, and °Be. Radioisotopes of hydrogen and carbon are of particular interest because they are major biological elements, and thus can be used as both chemical and biological tracers. Recently, particle reactive Be = 53.3 day) has been utilized as a valuable coastal tracer of short-term particle deposition and remobilization. ... 

A quantitative measure of isotope composition relative to the abundance of all isotopic forms found in nature. Values for those stable isotopes most commonly employed in biological tracer experiments are H, 99.985% ... 

Phosphorus-32, for example, produced by irradiating sulphur or natural phosphorus ( P) with high-energy particles, has a half-life of 14.8 days and can be rapidly taken up (in the form of phosphate) by body tissues such as muscles, the liver, bones, and teeth. De Hevesy found that different phosphorus compounds would be incorporated in a tissue-specific manner certain compounds were concentrated in the liver, for example. One can use stable isotopes as biological tracers too, since they are detectable atom by atom using mass spectrometry. De Hevesy observed that it takes deuterium twenty-six minutes to pass from ingested heavy water into urine. 

Elmore, D., Bhattacharyya, M. H., Sacco-Gibson, N., and Peterson, D. P. (1990). Calcium-41 as a long-term biological tracer for bone resorption. Nucl. Instrum. Methods Phys. Res. B52 531-535. 

A sample of 14CC>2 was to be mixed with ordinary CO2 (containing 12C) for a biological tracer experiment. In order that 10 cm3 (S.T.P.) of the diluted gas should have 104 disintegrations per minute, how may microcuries of radioactive carbon are needed to prepare 60 L of the diluted gas ... 

In order to understand these complex metabolic interactions more fully and to maximize the information obtained in these studies, we developed a detailed kinetic model of zinc metabolism(, ). Modeling of the kinetic data obtained from measurements of biological tracers by compartmental analysis allows derivation of information related not only to the transient dynamic patterns of tracer movements through the system, but also information about the steady state patterns of native zinc. This approach provides data for absorption, absorption rates, transfer rates between compartments, zinc masses in the total body and individual compartments and minimum daily requirements. Data may be collected without disrupting the normal living patterns of the subjects and the difficulties and inconveniences of metabolic wards can be avoided. 

The oral aluminium bioavailability of a representative food containing food additive acidic sodium aluminium phosphate (SALP), a leavening agent in baked goods, has been studied by accelerator mass spectrometry. In the experiments, rats were fed a special diet (biscuit containing 1 % or 2% acidic SALP, synthesized to contain A1). A1, which was used as a biological tracer, can be ultrasensitively analyzed by AMS. The rats received concurrent Al infusion for comparison with oral ingestion. ... 

Mass Spectrometry with electron impact ionization (EIMS). Mass i ectrometers wit electron impact ionization are widely used in biomedical research, primarily for identification and quantitation of organic molecules. Adaptation of EIMS to isotope ratio measurements of minerals has, therefore, considerable appeal for investigators Interested in using stable mineral Isotopes as biological tracers. 

Stable Isotope Techniques. Although the availability of radioiron isotopes has facilitated our understanding of iron nutrition, their utilization is becoming restricted for safety and ethical reasons, especially when infants, children, and women are involved. The availability of enriched stable iron isotopes (Table I) and methodologies for quantifying them make stable isotopes a feasible alternative to radioisotopes as biological tracers. Neutron activation analysis and mass spectrometry are currently available to nutritionists for quantifying stable isotopes of minerals. 

J.A. Dusenberry (2000). Steady-state single cell model simulations of photoacclimation in a vertically mixed layer implications for biological tracer studies and primary productivity. J. Mar. Syst., 24, 201-220. 

JORISSEN, F. J., FONTANIER, C. THOMAS, E. 2007. Paleoceanographical proxies based on deep-sea benthic foraminiferal assemblage characteristics. Im Hillaire-Marcel, C. De Vernal, A. (eds) Proxies in Late Cenozoic Paleoceanography. Volume 1 - Methods in Late Cenozoic Paleoceanography Ill-Biological Tracers and Biomarkers. Elsevier, pp. 263-325. 

Flack R and Elmore D (1998) Aluminum-26 as a biological tracer using accelerator mass spectrometry. In Zatta PF and Alfrey AC, ed. Aluminum toxicity in infant s health and disease, pp. 16-39. World Scientific, Singapore. 

---