Hi Wolfram/Chris,

It may be that Chris' researchers are referring to the dose regime as 0.15 g/KgTBW as some protocols tend to express the dosing needs in those terms rather than per Kg of body weight. In which case, the subjects would be receiving the typical dosage of 0.07 g/Kg body weight and consequently peak deuterium values like the ones we routinely see (ca. 800 permil).

Cheers

Steve

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On 24/02/2017 11:03, Wolfram Meier-Augenstein (pals) wrote:

Hi Chris,

Steve’s e-mail made me realise I forgot to mention the delta values I quoted were based on studies using a dose of 0.03 g/kg body weight.  Sorry.

Speaking of which, as Steve has pointed out typical dosage used DLW studies in adults rarely exceeds 0.06 or 0.07 g/kg.  A higher dosage such as 0.1 g/kg may be used in studies involving children or infants however.

Best,

Wolfram

Sent: 24 February 2017 10:21
Subject: Re: [ISOGEOCHEM] DLW method

In our experience the post dose enrichment in DLW and TBW experiments leads to a deuterium delta value of ca. 800 permil. It is of course dependent on the dose given to the subject and their actual TBW. So you have to expect some to be quite a bit higher. In most cases researchers use 0.07 g/Kg of body weight for the dosing of the D2O. This means that for an 80 Kg adult they will get 5.6 g of D2O which will be then diluted in 40 Kg of water (assuming subjects are 50% water). The calculated delta value (assuming the natural body water is -50 permil) for such a dilution would be 758 permil.

So if you used a dose of 0.15 g D2O per Kg body weight (i.e. you give them 12 g of D2O) you would get a calculated (i.e. expected) delta value of 1681 permil for an 80 Kg subject.

We use our own prepared standards to cover the range (the upper standard having a calibrated deuterium value of 1701 permil).

Steve

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On 24/02/2017 06:01, Christian Dietz wrote:

dear all,

I would like to know with which levels of D and d18O I would have to count in urine after administrating up to to 0.28g/kg 18O and 0.15g/kg 2H.

Or less specifically, those found in experiments to determine Total Body Water and Total Energy Expenditure.

It's for achieving IAEA standards covering the range I may have to expect.

thx, as always

Chris

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