Bomb Carbon-14 in Human Beings

Broecker, Wallace S.; Schulert, Arthur R.; Olson, Edwin A.

doi:10.1126/science.130.3371.331-a

Cited by 53 publications

(25 citation statements)

References 5 publications

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“…However, most human diets consist not only of terrestrially grown vegetal food and meat products (the latter generally have a longer delay time of 14 C from the atmosphere to human consumption than that of vegetal foods, according to Broecker et al 1959). Fish and seafood are usually also part of the diet, and the importance of this marine source can vary significantly regionally as well as individually.…”

Section: Introductionmentioning

confidence: 99%

Bomb-Pulse Dating of Human Material: Modeling the Influence of Diet

Georgiadou

Stenström

2010

Radiocarbon

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The atmospheric testing of nuclear weapons during the 1950s and early 1960s produced large amounts of radiocarbon. This 14C bomb pulse provides useful age information in numerous scientific fields, e.g. in geosciences and environmental sciences. Bomb-pulse dating can also be used to date human material (e.g. in forensics and medical science). Bomb-pulse dating relies on precise measurements of the declining 14C concentration in atmospheric carbon dioxide collected at clean-air sites. However, local variations in the 14C specific activity of air and foodstuffs occur, which are caused by natural processes as well as by various human activities. As 14C enters the human body mainly through the diet, variations of 14C concentration in foodstuffs need to be considered. The marine component of the diet is believed to be of particular importance due to the non-equilibrium in 14C specific activity between the atmosphere and aquatic reservoirs during the bomb pulse. This article reviews the 14C concentration in marine foodstuffs during the bomb-pulse era, and models how the marine component in one's diet can affect the precision of bomb-pulse dating of human material.

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Section: Introductionmentioning

confidence: 99%

Bomb-Pulse Dating of Human Material: Modeling the Influence of Diet

Georgiadou

Stenström

2010

Radiocarbon

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“…Excess 14C in the atmosphere, a result ofatomic weapons testing in the late 1950s and early 1960s, serves as a kinetic tracer for biogenic material (15). Weapons-related '4CO2 reaches the biosphere through photosynthesis, and reaches human tissues through the food chain, with a lag time of 1.0-1.5 yr (41)(42)(43). Thus, 14C prevalence in modern carbonaceous samples, including human tissues, provides a well-validated dating tool (15,43,44); '4C prevalence in human proteins can be assumed to reflect prevalence of '4C in the diet at the time of synthesis.…”

Section: Introductionmentioning

confidence: 99%

Marked longevity of human lung parenchymal elastic fibers deduced from prevalence of D-aspartate and nuclear weapons-related radiocarbon.

Shapiro

Endicott²,

Province³

et al. 1991

J. Clin. Invest.

575

367

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Normal structure and function of the lung parenchyma depend upon elastic fibers. Amorphous elastin is biochemically stable in vitro, and may provide a metabolically stable structural framework for the lung parenchyma. To test the metabolic stability of elastin in the normal human lung parenchyma, we have (a) estimated the time elapsed since the synthesis of the protein through measurement of aspartic acid racemization and (b) modeled the elastin turnover through'measurement ofthe prevalence of nuclear weapons-related "C. Elastin purified by a new technique from normal lung parenchyma was hydrolyzed; then the prevalences of D-aspartate and "4C were measured by gas chromatography and accelerator-mass spectrometry, respectively. D-aspartate increased linearly with age; K,,.,p (1.76x 10-3yr-') was similar to that previously found for extraordinarily stable human tissues, indicating that the age of lung parenchymal elastin corresponded with the age of the subject. Radiocarbon prevalence data also were consistent with extraordinary metabolic stability of elastin; the calculated mean carbon residence time in elastin was 74 yr (95% confidence limits, 40-174 yr). These results indicate that airspace enlargement characteristic of "aging lung" is not associated with appreciable new synthesis of lung parenchymal elastin. The present study provides the first tissue-specific evaluation of turnover of an extracellular matrix component in humans and underscores the potential importance of elastin for maintenance of normal lung structure. Most importantly, the present work provides a foundation for strategies to directly evaluate extracellular matrix injury and repair in diseases of lung (especially pulmonary emphysema), vascular tissue, and skin. (J. Clin. Invest. 1991.

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“…Relevantly, Broecker et al analyzed C14 incorporation into the food supply and human tissue and concluded that there is a delay of up to 2 years for solid tissue [20]. Such a delay substantially affects turnover levels in subjects meeting both of two criteria: (1) true turnover is low (∼1% annually) such that hearts at time of subject death are substantially composed of original CMs and (2) subjects are born in a time of rapidly changing atmospheric C14 such that a small delay results in substantially under-estimated initial C14 values.…”

Section: Resultsmentioning

confidence: 99%

Hybrid Mathematical Model of Cardiomyocyte Turnover in the Adult Human Heart

Elser

Margulies

2012

PLoS ONE

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RationaleThe capacity for cardiomyocyte regeneration in the healthy adult human heart is fundamentally relevant for both myocardial homeostasis and cardiomyopathy therapeutics. However, estimates of cardiomyocyte turnover rates conflict greatly, with a study employing C14 pulse-chase methodology concluding 1% annual turnover in youth declining to 0.5% with aging and another using cell population dynamics indicating substantial, age-increasing turnover (4% increasing to 20%).ObjectiveCreate a hybrid mathematical model to critically examine rates of cardiomyocyte turnover derived from alternative methodologies.Methods and ResultsExamined in isolation, the cell population analysis exhibited severe sensitivity to a stem cell expansion exponent (20% variation causing 2-fold turnover change) and apoptosis rate. Similarly, the pulse-chase model was acutely sensitive to assumptions of instantaneous incorporation of atmospheric C14 into the body (4-fold impact on turnover in young subjects) while numerical restrictions precluded otherwise viable solutions. Incorporating considerations of primary variable sensitivity and controversial model assumptions, an unbiased numerical solver identified a scenario of significant, age-increasing turnover (4–6% increasing to 15–22% with age) that was compatible with data from both studies, provided that successive generations of cardiomyocytes experienced higher attrition rates than predecessors.ConclusionsAssignment of histologically-observed stem/progenitor cells into discrete regenerative phenotypes in the cell population model strongly influenced turnover dynamics without being directly testable. Alternatively, C14 trafficking assumptions and restrictive models in the pulse-chase model artificially eliminated high-turnover solutions. Nevertheless, discrepancies among recent cell turnover estimates can be explained and reconciled. The hybrid mathematical model provided herein permits further examination of these and forthcoming datasets.

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Bomb Carbon-14 in Human Beings

Cited by 53 publications

References 5 publications

Bomb-Pulse Dating of Human Material: Modeling the Influence of Diet

Bomb-Pulse Dating of Human Material: Modeling the Influence of Diet

Marked longevity of human lung parenchymal elastic fibers deduced from prevalence of D-aspartate and nuclear weapons-related radiocarbon.

Hybrid Mathematical Model of Cardiomyocyte Turnover in the Adult Human Heart

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