Application of stable isotopes in medicine
1. Stable isotope of Fe in human body: tracer of genetic diseases
Fe is particularly important in human biology because hemoglobin, which contains iron divalent, is the main carrier of oxygen in the blood. Other Fe is stored in the liver and kidneys, mainly Fe ferritin, which ACTS as a hydrated iron oxide wrapped in a protein shell. Studies have shown that Fe isotopes in the blood become heavier after blood loss, which is explained by the fact that Fe is quickly replenished from the liver and kidneys to compensate for the loss of blood. The first disease to be studied from the perspective of the natural stable isotopes of Fe is hereditary hemochromatosis.
2. Stable Cu isotope in human body: diagnostic marker of potential cancer
Cu ACTS as both a catalyst and a structural component in several important enzymes. Cu may be a valuable indicator of rapidly developing diseases such as cancer. Patients with cancer often have high levels of Cu in their serum. The use of thiomolybdate and the chelate of d-penicillamine to reduce Cu levels in humans has been licensed for cancer treatment. Cu isotopes have great potential as cancer markers. The strong Cu isotope signal seems to be related to the chelation of Cu with lactic acid.
The serum lactic acid itself is strictly controlled by the membrane transport process, and the metabolism occurs, so it is difficult to represent the intracellular lactic acid. Instead, the Cu isotopes in the blood reflect the metabolic state of the cell and its degree of substitution for normal glycolysis. Thus, the abundance of Cu isotopes in the serum appears to be a strong potential biomarker of cancer growth and spread.
3. Stable isotope of Ca in human body: a medical diagnostic tool for bone diseases
99% of the Ca in our bodies is in our bones in the form of hydroxyapatite, and bone loss is a dynamic process. Ca is the first unconventional element whose six isotope variations have been investigated. Ca isotopes can be routinely analyzed using two methods: thermoelectric ionization mass spectrometry (TIMS) and multi-reception inductively coupled plasma mass spectrometry (Mc-icpms). Two main conclusions include: one is that as Ca passes through the food chain, it becomes a lighter isotope; Second, the Ca in the skeleton is a light isotope. Ca isotopes can be used to quantify the amount of calcium flowing out and in from bone without the need to add a tracer to the diet. This is also related to the Ca study of osteoporosis, which is particularly common in older women.
The development of stable metal isotopes as biomarkers is promising, and the field I propose to call "medical isotope metallography". The effect of specific ligands in body fluids on isotope variability can be predicted from the first principle, which identifies specific biological pathways. The importance of isotope composition analysis, which does not require a strict timetable, is that many samples left over from the past can still be analysed many years after collection. Finally, different metals have different turnaround times in the body, so isotope metallography can provide sensitive and broad potential markers for describing different types of disease on different time scales.