metal isotope ratio analysis in medicine

fractionation is

proportional to mass difference between the isotopes

iron function in haemoglobin

carries oxygen

chemical reactions involving these metals

may result in fractionation of their isotopes

Disease may alter metal isotope fractionation

allowing possibility of metal isotope ratios as diagnostic and prognostic tools

iron isotopes in the body

found in haemoglobin, and is also stored in the liver, spleen and bone marrow

iron absorption

from the intestine

iron isotopic compositions

differ in different parts of the body

iron status

amount of iron in the body and its biological availability

Two iron disorders cause changes in blood iron isotope composition

1. Haemochromatosis

2. ACD (anaemia of chronic diseases)

Blood 57Fe and 56Fe reflect

extent of iron uptake from intestine and the redox changes associated with the binding of iron to, or its release from, ferritin, a protein that stores iron

liver cancers

mostly due to hepatitis B or C infection, or alcohol exposure

symptoms

often only seen at an advanced stage

copper isotopes

heavier in liver tumour tissue than in healthy liver

In situ liver copper isotope analysis by LA-MC-ICP-MS

 confirms that tumours contain heavier copper isotopes than healthy liver tissue

diagnostic and prognostic tool

LA-ICP-MS permits high resolution study of copper isotope composition which will help to determine mechanism of isotope fractionation

multiple myeloma

 a cancer of the plasma cells which can form a mass in bone marrow or soft tissue

diagnosed

from unusual antibodies in blood or urine

disease results in

bone destruction, including osteoporosis and the formation of bone lesions, especially on the spinal cord - it is hard to detect by X-ray until advanced

Bone formation favours incorporation of light calcium isotopes

lower 44/42Ca (= 44Ca/42Ca ratio relative to standard) in serum of patients with active disease compared  to those with non-active stage of disease

confirms hypothesis

that bone destruction releases isotopically light Ca (more negative 44/42Ca) into serum. This is a potential diagnostic tool