Accelerator mass spectrometry of ultra-small samples with applications in the biosciences

Salehpour, Mehran; Håkansson, Karl; Possnert, Göran

doi:10.1016/j.nimb.2012.08.054

Cited by 27 publications

(36 citation statements)

References 19 publications

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“…This is to present the total scatter in the measurement that has been recorded so far. The updated data are consistent with our previous data containing 1329 points (Salehpour et al 2013). It is noted that the current is more or less constant for mg samples down to about 100-µg C samples.…”

Section: Ultra-small Samplessupporting

confidence: 89%

“…Figure 3 shows the uncorrected isotopic ratio against the sample mass for 360 oxalic acid II samples collected during 70 consecutive AMS experiments, over a period of about 1 yr. No data points have been excluded in order to display the total variation and scatter. In accordance with our previous measurements (Salehpour et al 2013), the pM mass dependence is weak down to ~10 µg C. As an example, a 10-µg C sample has typically a few percent lower pMC value compared to a mg sample. The mass dependence is due to the carbon background and can be corrected for as described in Salehpour et al (2013).…”

supporting

confidence: 91%

“…In accordance with our previous measurements (Salehpour et al 2013), the pM mass dependence is weak down to ~10 µg C. As an example, a 10-µg C sample has typically a few percent lower pMC value compared to a mg sample. The mass dependence is due to the carbon background and can be corrected for as described in Salehpour et al (2013). The background carbon originating from 14 C-free origins (dead carbon) and carbon from the laboratory atmosphere (Modern carbon) were determined as follows: Two series of dead carbon samples and modern samples at various masses were prepared and measured with AMS.…”

supporting

confidence: 91%

“…The ultra-small sample (USS) method addresses sample sizes from about 500 µg C down to a few µg C and has also been described in detail in Salehpour et al (2013). Thus, only a brief description is given here.…”

Section: Ultra-small Samplesmentioning

confidence: 99%

“…There is a dependence of the extracted ion current on the mass of the sample as can be seen in Figure 1. The data contains over 3600 data points for samples prepared using the USS preparation method, updated since the last report (Salehpour et al 2013). No data points have been excluded even though a few samples should have been rejected as outliers due to low current.…”

Section: Ultra-small Samplesmentioning

confidence: 99%

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Life Science Applications Utilizing Radiocarbon Tracing

Salehpour

2013

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Life science applications utilizing radiocarbon tracing. ABSTRACT. Radiocarbon-based accelerator mass spectrometry (AMS) facilities at Uppsala University include a measurement center for archaeological applications and a separate entity dedicated to life science research. This paper addresses the latter, with the intention of giving an overall description of the biomedical activities at our laboratory, as well as presenting new data. The ultra-small sample preparation method, which can be used down to a few µg C samples, is briefly outlined and complemented with new results. Furthermore, it is shown that the average secondary ion current performance for small samples can be improved by increasing the distance between the cathode surface and the pressed graphite surface. Finally, data is presented for a new application: Amyloidoses are a group of diseases where the conformational changes in specific proteins' structure lead to the formation of extracellular deposits that spread and increase in mass and eventually may lead to total organ failure and death. The formation timeframe is unknown and yet it is an important clue for the elucidation of the mechanism. We present results on bomb-peak dating of 4 different types of purified amyloid proteins from human postmortem heart and spleen samples. The data indicates that the average measured age of the carbon originating from the systemic amyloid types studied here correspond to a few years before the death of the subject. This suggests that a major part of the plaque formation takes place during the last few years before death, rather than as an accumulation of plaque deposits over decades.

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Section: Ultra-small Samplessupporting

confidence: 89%

supporting

confidence: 91%

supporting

confidence: 91%

Section: Ultra-small Samplesmentioning

confidence: 99%

Section: Ultra-small Samplesmentioning

confidence: 99%

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Life Science Applications Utilizing Radiocarbon Tracing

Salehpour

2013

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Dynamics of Hippocampal Neurogenesis in Adult Humans

Spalding

Bergmann

Alkass

et al. 2013

Cell

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1,589

1,273

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Adult-born hippocampal neurons are important for cognitive plasticity in rodents. There is evidence for hippocampal neurogenesis in adult humans, although whether its extent is sufficient to have functional significance has been questioned. We have assessed the generation of hippocampal cells in humans by measuring the concentration of nuclear bomb test-derived 14C in genomic DNA and we present an integrated model of the cell turnover dynamics. We found that a large subpopulation of hippocampal neurons, constituting one third of the neurons, is subject to exchange. In adult humans, 700 new neurons are added per day, corresponding to an annual turnover of 1.75% of the neurons within the renewing fraction, with a modest decline during aging. We conclude that neurons are generated throughout adulthood and that the rates are comparable in middle aged humans and mice, suggesting that adult hippocampal neurogenesis may contribute to human brain function.

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Neurogenesis in the Striatum of the Adult Human Brain

Ernst¹,

Alkass²,

Bernard³

et al. 2014

Cell

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727

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In most mammals, neurons are added throughout life in the hippocampus and olfactory bulb. One area where neuroblasts that give rise to adult-born neurons are generated is the lateral ventricle wall of the brain. We show, using histological and carbon-14 dating approaches, that in adult humans new neurons integrate in the striatum, which is adjacent to this neurogenic niche. The neuronal turnover in the striatum appears restricted to interneurons, and postnatally generated striatal neurons are preferentially depleted in patients with Huntington's disease. Our findings demonstrate a unique pattern of neurogenesis in the adult human brain.

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Accelerator mass spectrometry of ultra-small samples with applications in the biosciences

Cited by 27 publications

References 19 publications

Life Science Applications Utilizing Radiocarbon Tracing

Life Science Applications Utilizing Radiocarbon Tracing

Dynamics of Hippocampal Neurogenesis in Adult Humans

Neurogenesis in the Striatum of the Adult Human Brain

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