TXA2 with a half-life of approximately 30 sec under physiologic conditions was measured using its stable metabolite TXB2, and PGI2 using its stable metabolite 6-keto-prostaglandin F1α [ 16].
Body water was measured using a stable isotope dilution procedure.
Total body water was measured using a stable isotope dilution technique [ 20].
Protein kinetics were measured using continuous stable isotope-labeled phenylalanine and tyrosine infusions.
The inhibition of brain Aβ production by semagacestat was measured using the stable isotope kinetic effect assay.
Breast-milk intake was measured using a stable isotope tracer technique, ('dose-to-the-mother-method'), currently the gold standard method for such determinations.
The stable isotope (δ2H and δ18O) compositions of the waters (rivers, hand-dug wells and boreholes) were measured using the Liquid Water Stable Isotope analyser [based on the off-axis integrated cavity output spectroscopy (OA-ICOS) via laser absorption].
NAA (µmol/L) was measured using a modified stable isotope dilution Gas Chromatography-Mass Spectrometry (GC-MS) method essentially as described by Jakobs et al. [7] In short, 1 nmol [D3]-NAA was added as internal standard to 100 µl of CF. This was also added to aqueous standards.
Urine creatinine will be measured using a chromatographic stable isotope dilution electrospray mass spectrometry-mass spectrometry (MSMS) method.
