Substantial replacement of mammalian body carbon with carbon-13

Gregg, Charles T.; Hutson, J.Y.; Prine, J.R.; Ott, Donald G.; Furchner, J.E.

doi:10.1016/0024-3205(73)90068-4

Cited by 53 publications

(27 citation statements)

References 6 publications

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“…Some insights can be gleaned from feeding animals 13 Cdepleted diets (C3) followed by C4 diets upon weaning and vice versa, to see how different tissues are affected. Repeating the toxicology experiments (26)(27)(28) (vs) without prematurely sacrificing the animals may also reveal the difference in longevity between 'heavy' and 'light' animals. Different percentages of isotopes should be tried to establish if there is an optimal ratio between heavy and light atoms.…”

Section: Conclusion and Suggested Experimentsmentioning

confidence: 99%

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Do “heavy” eaters live longer?

Shchepinov¹

2007

BioEssays

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A new hypothesis is put forward, linking cellular endurance with dietary consumption of stable heavy isotopes. Due to the isotope effect, biomolecules that incorporate heavier isotopes give rise to more stable molecular structures with increased resistance to damages associated with aging and age-related disease. The inclusion of heavy isotopes might be either active (selection for heavier isotopes) or passive (incorporation reflecting the existing abundance). The hypothesis links consumption of foods relatively rich in heavy isotopes (such as (13)C and D, derived from C4-plants), especially at the early stages of the organism's development, with enhanced longevity. Implications of diets and intestinal microflora are also discussed.

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Section: Conclusion and Suggested Experimentsmentioning

confidence: 99%

“…(26) Experiments on mouse embryos (27,28) also revealed no toxicity or abnormalities of any kind. The animals were sacrificed to study their inner organs, so no longevity data were collected.…”

mentioning

confidence: 96%

Do “heavy” eaters live longer?

Shchepinov¹

2007

BioEssays

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“…At the time of death, the animals appeared healthy and both macroscopic and microscopic postmortem examinations were normal. The 13 C contents of a wide variety of tissues from both animals were enriched to approximately 60 at.% 13 C, with little difference in 13 C labeling between 127 and 234 days (67). Although obviously limited, this truly unique experiment (at an extraordinary isotopic cost) showed that mice appear to be able to tolerate far greater replacement of body 12 C with 13 C than is possible when deuterium replaces the proton.…”

Section: Iconsmentioning

confidence: 94%

Nutrition from the Inside Out

Bier

2017

Annu. Rev. Nutr.

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Nearly 50 years ago, I set out to investigate the clinical problem of hypoglycemia in children with illnesses that limited their food intake. My goal was to gather accurate and precise measurable data. At the time, I wasn't interested in nutrition as a discipline defined in its more general or popular sense. To address the specific problem that interested me required development of entirely new methods based on stable, nonradioactive tracers that satisfied the conditions of accuracy and precision. At the time, I had no inclination of the various theoretical and practical problems that would have to be solved to achieve this goal. Some are briefly described here. Nor did I have the slightest idea that developing the field would result in a fundamental change in how human clinical investigation was conducted, with the eventual replacement of radiotracers with stable isotopically labeled ones, even for adult clinical investigation. Additionally, I had no inclination that the original questions would open avenues to much broader questions of practical nutritional relevance. Moreover, only much later as the editor of The American Journal of Clinical Nutrition did I appreciate the policy implications of how nutritional data are presented in the scientific literature. At least in part, less accurate and precise measurements and less than full transparency in reporting nutritional data have resulted in widespread debate about the public policy recommendations and guidelines that are the intended result of collecting the data in the first place. This article provides a personal recollection (with all the known faults of self-reporting and retrospective memory) of the journey that starts with measurement certainty and ends with policy uncertainty.

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“…Gregg et al 5 fed carbon-13-enriched algae to mice and raised the carbon-13 content of their total body pool to the 60%-70% level without providing any discernible effects. In the laboratory of Wolfe et al and his colleagues 6 in the Glucose is immediately phosphorylated after being taken up inside the cells to produce glucose 6-phosphate (G-6-P), following which glycolysis occurs, converting glucose into pyruvate.…”

Section: Stable Isotope Tracersmentioning

confidence: 99%

Assessment of In Vivo Glucose Kinetics Using Stable Isotope Tracers to Determine Their Alteration in Humans During Critical Illness

2000

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Glucose plays a central role in energy metabolism, and alterations in its utilization have been reported under a variety of physiological and pathological conditions. The extent and direction of its changes provide useful information to promote the understanding of pathophysiology. The regulation of in vivo glucose kinetics is important because it is closely linked to energy production and the control of amino acid and protein metabolism. Although alterations in glucose kinetics have been demonstrated in critically ill patients, the mechanisms responsible are not well understood. The measurement of glucose kinetics in humans using stable isotopic glucose tracers provides a better understanding of the responses to nutritional support in these patients. While tracer methods have been used to quantitatively measure in vivo kinetics in patients with a variety of critical illnesses as well as in normal volunteers during fasting and exercise in European countries and the United States, they have not received the same attention in Japan. Stable isotopic glucose tracers can be safely given to humans since they are themselves naturally occurring substances, accounting for a small percentage of the total, depending on the isotopic species. The intravenous administration of a glucose tracer allows quantitative assessment of in vivo glucose kinetics under a variety of conditions. This method has wide potential for obtaining kinetic data on all aspects of in vivo glucose metabolism, with major advantages for conducting metabolic studies in humans.

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Substantial replacement of mammalian body carbon with carbon-13

Cited by 53 publications

References 6 publications

Do “heavy” eaters live longer?

Do “heavy” eaters live longer?

Nutrition from the Inside Out

Assessment of In Vivo Glucose Kinetics Using Stable Isotope Tracers to Determine Their Alteration in Humans During Critical Illness

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