Determination, stable isotope enrichment and kinetics of direct-reacting copper in blood plasma

Buckley, W. T.; Vanderpool, Richard A.; Godfrey, David V.; Johnson, Phyllis E.

doi:10.1016/0955-2863(96)00100-3

Cited by 17 publications

(25 citation statements)

References 14 publications

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“…The method was found to be suitable for determining the concentration of EX Cu in plasma as well as the stable isotope ratio of EX Cu obtained from in vivo tracer studies. Although the quantity of EX Cu in plasma varies considerably from species to species, it also varies considerably with the method of determination (Buckley et al 1996). The values for EX Cu determined with the isotope dilution method (Buckley et al 1996) agree reasonably well with the original DDC colorimetric method (Gubler et al 1953), an immunochemistry procedure ( Van den Hamer 1988;Louro et al 2000) and an electrophoresis procedure (Bearn and Kunkel 1954), but are much lower than those determined with a gel filtration procedure (Weiss and Linder 1985;Wirth and Linder 1985).…”

Section: Introductionmentioning

confidence: 65%

“…The half-life of the exchangeable (EX) Cu fraction in vivo is much less than that of ceruloplasmin Cu. The exchangeable fraction includes Cu immediately absorbed from the gut (Gordon et al 1987;Buckley et al 1996). Evidence presented earlier indicates that EX Cu determined by isotope dilution analysis is physiologically significant (Buckley et al 1996).…”

Section: Introductionmentioning

confidence: 97%

“…The exchangeable fraction includes Cu immediately absorbed from the gut (Gordon et al 1987;Buckley et al 1996). Evidence presented earlier indicates that EX Cu determined by isotope dilution analysis is physiologically significant (Buckley et al 1996). Because of its central role in distribution of absorbed Cu, plasma EX Cu has been included as a compartment in kinetic models of Cu metabolism (Buckley 1991;Turnlund 1998).…”

Section: Introductionmentioning

confidence: 98%

“…We previously described a method of determining EX Cu based on stable isotope dilution analysis (Buckley et al 1996). The method was found to be suitable for determining the concentration of EX Cu in plasma as well as the stable isotope ratio of EX Cu obtained from in vivo tracer studies.…”

Section: Introductionmentioning

confidence: 99%

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Analytical variables affecting exchangeable copper determination in blood plasma

Buckley

Vanderpool²

2008

Biometals

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To resolve discrepancies observed in the determination of plasma exchangeable Cu (also called direct reacting Cu or loosely bound Cu) by several methods, plasma storage techniques and various aspects of a stable isotope dilution procedure for exchangeable Cu were evaluated. Results indicated that the exchangeable Cu fraction of plasma increased with storage at room temperature, at 5 degrees C and when subjected to repeated freeze/thaw cycles. Samples could be safely stored at -65 degrees C. Exchange between added 65Cu2+ and endogenous plasma Cu rapidly went to completion in the isotope dilution procedure. Analytical results were unaffected by shaking method, sample size or the presence of heparin. A small difference was observed between serum and plasma. The determination of exchangeable Cu did not vary over a period of 4 h when plasma was exposed to 1.6 x 10(-4)-M sodium diethyldithiocarbamate (used in the isotope dilution method) but steadily increased when exposed to 1.1 x 10(-2)-M sodium diethyldithiocarbamate, which suggested that tightly bound Cu (probably in ceruloplasmin) was exchanging with isotopic tracer at the higher concentration. Determination of exchangeable Cu was constant from pH 7.2-8.5 but increased substantially at higher pH. Complete recovery of natural Cu added to plasma was obtained. Studies in solution indicated that 65Cu2+ exchanged readily with albumin- and amino acid-bound Cu. Ultrafiltration of plasma yielded a Cu fraction about half that of the exchangeable Cu fraction. We conclude that the stable isotope dilution procedure for plasma exchangeable Cu yields reliable, physiologically meaningful results.

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Section: Introductionmentioning

confidence: 65%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Analytical variables affecting exchangeable copper determination in blood plasma

Buckley

Vanderpool²

2008

Biometals

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“…This value is higher than that found in the only other two studies that have attempted to measure the half-life of non-CP-bound Cu. Buckley et al (1996) reported lower half-lives (8·7 and 12·3 min) in two volunteers after IV infusion with a 65 Cu label. These values agreed with those of D' Addabbo et al (1971) of 8·5 and 10 min for the half-life of 64 Cu in two subjects after IV injection.…”

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confidence: 99%

Use of stable isotopes and mathematical modelling to investigate human mineral metabolism

Dainty

2001

nutr res rev

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Individuals have varying needs for minerals that are dependent, amongst other things, on their lifestyle, age and genetic makeup. Knowledge of exact individual nutritional requirements should lead to better health, increased quality of life and reduced need for expensive medical care. Bioavailability, nutrient-gene interactions and whole-body metabolism all need to be investigated further if we are to progress towards the goal of defining optimal health and nutritional status. The discussion which follows will critically review the latest developments in the area of metabolism for several of the minerals that are essential for human health: Ca, Zn, Cu and Se. Stable-isotope tracers and mathematical modelling are some of the tools being used to facilitate the greater understanding in uptake, utilisation and excretion of these minerals. Stable isotopes, administered in physiological doses, present little or no risk to volunteers and allow metabolic studies to be carried out in vulnerable population groups such as children and pregnant women. Intrinsic labelling of foodstuffs ensures that the tracer and the native mineral will behave similarly once inside the body. Advances in computing power and software dedicated to solving nutritional problems have made it possible for investigators to use mathematical modelling in their experimental work. Mineral metabolism is ideally suited to a form of modelling known as compartmental analysis, which allows rates of mineral transfer and sizes of mineral stores to be calculated accurately without the need for invasive sampling of body tissues. Stable isotopes: Mathematical modelling: Mineral metabolismNutrition Research Reviews (2001) , IntroductionMost minerals have several naturally-occurring stable isotopes, all with a fixed abundance. In order to follow the metabolism of a mineral, it is necessary to ingest it in an altered form so that it can be distinguished from the naturally-abundant mineral. The form of the ingested mineral can be altered by enriching one of the low-abundance isotopes. This so-called 'tracer' or 'label' is injected and/or taken orally and its appearance in the plasma, urine and faeces can be monitored over several days. The concept of a tracer is important in isotope work. A true tracer is one that does not perturb the system it is investigating. Only radioisotopes can be called true tracers, since they are administered in extremely small quantities. The term 'label' is more appropriate for stable isotopes, since they are usually given in quantities equivalent to the amount received in the normal diet. The word 'tracer' is, however, still used in some stable-isotope studies with the implicit understanding that it will almost certainly perturb the system under investigation. The underlying assumption in this type of work is that the label (or tracer) behaves in the same kinetic way as the naturally-abundant mineral (sometimes called the tracee), otherwise the use of labels to mimic the behaviour of the native mineral is invalid. There must be no discri...

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Cadmium Absorption in Women Fed Processed Edible Sunflower Kernels Labeled with a Stable Isotope of Cadmium, 113Cd

Vanderpool

Reeves

2001

Environmental Research

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Determination, stable isotope enrichment and kinetics of direct-reacting copper in blood plasma

Cited by 17 publications

References 14 publications

Analytical variables affecting exchangeable copper determination in blood plasma

Analytical variables affecting exchangeable copper determination in blood plasma

Use of stable isotopes and mathematical modelling to investigate human mineral metabolism

Cadmium Absorption in Women Fed Processed Edible Sunflower Kernels Labeled with a Stable Isotope of Cadmium, 113Cd

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