Life Science Applications Utilizing Radiocarbon Tracing

Abstract

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.

Small sample Accelerator Mass Spectrometry for biomedical applications

“…Unlike Khosh et al [14] we have reported that TiH 2 is not necessary for the graphitization process [11,12]. The sealed graphitization tube is inserted in a heater block and the graphitization takes place at 550°C for 6 h.…”

“…The USS sample preparation method has been reported earlier [11,12] and is therefore only briefly outlined here. The small samples size sample preparation method differs from the standard mg-AMS in a number of ways, some of which are mentioned here.…”

“…As an example, the human hippocampus, a special region in the brain which is partially responsible for memory and spatial orientation gives rise to only about 15 lg C per human. We have been involved with USS AMS for the last 5 years and have developed a sample preparation method to address our specific needs [11,12]. Our method is based on combining the sample preparation methods of Santos et al [13] and Khosh et al [14] as well as using the methodology of Hua et al [15].…”

Application of zinc sealed tube graphitization on sub-milligram samples using EnvironMICADAS

“…Recently we have adopted an alternative sealed tube method for 1 mg carbon sample size, where the zinc reagent is used as sole reduction agent (Zn-method) [9][10][11] and optimized it for the MICADAS AMS instrument (under publication). This alternative method has already been successfully applied and used in other labs for micrograms sample size [12][13][14]. This way the hydrogen is eliminated from the reaction system and the methane formation is prevented.…”

Bomb pulse biology

“…This volume contains papers that describe specialized approaches to measure samples containing less than 10 μg C [41–44]. We find drying liquid samples in a lyophilizer using an oilless pump works well to minimize sample loss and keep fossil and contemporary backgrounds low.…”