Highly Tritiated Water Processing by Isotopic Exchange

2015 ◽  
Vol 67 (3) ◽  
pp. 563-566 ◽  
Author(s):  
W. M. Shu ◽  
I. Cristescu ◽  
R. Michling ◽  
D. Demange ◽  
R. S. Willms ◽  
...  
Keyword(s):  
Isotopic Exchange ◽  
Tritiated Water

Capture and Isotopic Exchange Method for Water and Hydrogen Isotopes on Zeolite Catalysts up to Technical Scale for Pre-Study of Processing Highly Tritiated Water

2015 ◽  
Vol 67 (3) ◽  
pp. 483-486 ◽  
Author(s):  
Robert Michling ◽  
Adalbert Braun ◽  
Ion Cristescu ◽  
Helmut Dittrich ◽  
Manfred Glugla ◽  
...  
Keyword(s):  
Isotopic Exchange ◽  
Tritiated Water ◽  
Hydrogen Isotopes ◽  
Zeolite Catalysts ◽  
Exchange Method

Behavior of Hydrophobic Isotopic Exchange Catalysts in the Presence of Tritiated Water

2005 ◽  
Vol 48 (1) ◽  
pp. 688-691 ◽  
Author(s):  
C. Postolache ◽  
Lidia Matei ◽  
Gh. Ionita
Keyword(s):  
Isotopic Exchange ◽  
Tritiated Water

scholarly journals Proton transfer in methylmalonyl-CoA epimerase from Propionibacterium shermanii. The reaction of (2R)-methylmalonyl-CoA in tritiated water

1983 ◽  
Vol 213 (3) ◽  
pp. 643-650 ◽  
Author(s):  
J Q Fuller ◽  
P F Leadlay
Keyword(s):  
Proton Transfer ◽  
Isotopic Exchange ◽  
Tritiated Water ◽  
Specific Radioactivity ◽  
Proton Donor ◽  
Partial Reaction ◽  
Propionibacterium Shermanii ◽  
Catalysed Reaction ◽  
Donor And Acceptor

The reaction catalysed by methylmalonyl-CoA epimerase from Propionibacterium shermanii was studied in tritiated water, in the direction with (2R)-methylmalonyl-CoA as substrate, under ‘irreversible’ conditions. After partial reaction, even when most of the substrate had been converted into product (isolated as propionyl-CoA) essentially no solvent tritium appeared in residual (2R)-methylmalonyl-CoA. The product, however, did contain tritium, and the specific radioactivity of the (2S)-epimer was deduced to be 0.33 times that of the solvent. These results provide further support for the mechanism proposed for the epimerase-catalysed reaction in the accompanying paper [Leadlay & Fuller (1983) Biochem. J. 213, 635-642], in which two enzyme bases act respectively as proton donor and acceptor. The observed low discrimination against solvent tritium entering the product can be accounted for by a mechanism in which the release of product is slow, and the re-protonation step on the enzyme is reversible, without leading to isotopic exchange with the solvent.

UPTAKE OF OXYTOCIN IN TISSUES AFTER INTRAVENOUS ADMINISTRATION OF TRITIATED OXYTOCIN IN RATS

1969 ◽  
Vol 61 (3) ◽  
pp. 432-440 ◽  
Author(s):  
Ingvar Sjöholm ◽  
Gunnar Rydén
Keyword(s):  
Skeletal Muscle ◽  
Distribution Pattern ◽  
Intravenous Injection ◽  
Intravenous Administration ◽  
Time Course ◽  
Tritiated Water ◽  
Preferential Distribution ◽  
Time Period ◽  
Initial Uptake

ABSTRACT The distribution of oxytocin in the kidneys, liver, uterus and skeletal muscle of the rat was followed during 10 min after intravenous injection of tritium labelled oxytocin. Oxytocin was found to be taken up and degraded mainly in the kidneys and the liver. After 150 seconds no intact oxytocin could be detected in these organs. The time course of the distribution of the radioactivity in the liver and the skeletal muscle showed no noteworthy characteristics, whereas a different course was found in the kidneys and in the uterus. In the kidneys, the radioactivity increased continuously from 60 to 200 seconds after the injection, indicating an accumulation of oxytocin or its metabolites in the kidneys. In the uterus a high initial uptake was observed, followed by a decrease of the radioactivity from 60 to 100 seconds after the injection. This distribution pattern was specific to oxytocin, since the uptake of tritiated tyrosine and tritiated water was almost constant during the same time period. These findings may indicate a preferential distribution of oxytocin to the uterus.

Click Chemistry Expedited Radiosynthesis: Sulfur [18F]fluoride Exchange of Aryl Fluorosulfates

2019 ◽  
Author(s):  
Qinheng Zheng ◽  
Hongtao Xu ◽  
Hua Wang ◽  
Wen-Ge Han Du ◽  
Nan Wang ◽  
...  
Keyword(s):  
Click Chemistry ◽  
High Performance ◽  
Isotopic Exchange ◽  
Tumor Imaging ◽  
Radiochemical Yield ◽  
Exchange Method ◽  
Molar Activity ◽  
Positron Emission ◽  
Sulfur Fluoride

The lack of simple, efficient [<sup>18</sup>F]fluorination processes and new target-specific organofluorine probes remains the major challenge of fluorine-18-based positron emission tomography (PET). We report here a fast isotopic exchange method for the radiosynthesis of aryl [<sup>18</sup>F]fluorosulfate based PET agents enabled by the emerging sulfur fluoride exchange (SuFEx) click chemistry. The method has been applied to the fully-automated <sup>18</sup>F-radiolabeling of twenty-five structurally diverse aryl fluorosulfates with excellent radiochemical yield (83–100%) and high molar activity (up to 281 GBq µmol<sup>–1</sup>) at room temperature in 30 seconds. The purification of radiotracers requires no time-consuming high-performance liquid chromatography (HPLC), but rather a simple cartridge filtration. The utility of aryl [<sup>18</sup>F]fluorosulfate is demonstrated by the <i>in vivo</i> tumor imaging by targeting poly(ADP-ribose) polymerase 1 (PARP1).

Variation in the wheat intake of individual sheep measured by use of labelled grain: behavioural influences

1981 ◽  
Vol 21 (111) ◽  
pp. 395 ◽  
Author(s):  
E Juwarini ◽  
B Howard ◽  
BD Siebert ◽  
JJ Lynch ◽  
RL Elwin
Keyword(s):  
Dominance Hierarchy ◽  
Tritiated Water ◽  
Supplementary Feeding ◽  
Previous Experience ◽  
Feed Consumption ◽  
Wheat Grain ◽  
Accurate Calculation ◽  
Early Introduction

A preliminary experiment with sheep in pens demonstrated that wheat grain could be labelled with tritiated water so that when fed it could provide data that would allow accurate calculation of individual feed consumption. This techinque was used with two groups of sheep fed supplementary wheat grain in paddocks. Half of the animals had previous experience of grain feeding some eight months earlier and the others had not eaten grain. Individual diversity of intake could be estimated usefully by tritium labelling of wheat, which was fed to the sheep in a group. The experiment showed that there was a threefold difference in the amount of wheat eaten between the lowest and highest intakes. Further, animals with previous experience of grain feeding consumed the entire ration initially, but those without previous experience did not consume all of the ration until two weeks after wheat feeding began. Over the period of measurement the experienced sheep consumed about 13% more wheat than the non-experienced group. There were insufficient aggressive acts to establish a dominance hierarchy in either group, although the experienced sheep were more aggressive than the others. Aggressiveness by one sheep towards other sheep did not result in higher wheat intakes by the former compared with other sheep in the group. The results are discussed in terms of the variability in acceptance of such supplements by animals, and of the value, later in life, of early introduction of supplementary feeding.

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