TABLE 3.
Fractional incorporation rates [median (25th, 75th percentile)] of CIRAA's estimated from biweekly measurements1
| Tissue | CIRAA | Number converged | Median λ2 (25th, 75th) | Median t0.5,3 wk | Median t0.9, wk |
|---|---|---|---|---|---|
| Plasma | Ala | 13 | 0.31 (0.15, 0.53) | 2.2 | 7.4 |
| Plasma | Val | 9 | 0.25 (0.19, 0.37) | 2.8 | 9.2 |
| Plasma | Leu | 13 | 0.38 (0.19, 0.49) | 1.8 | 6.1 |
| Plasma | Thr | 7 | 0.39 (0.23, 0.51) | 1.8 | 5.9 |
| Plasma | Ser | 10 | 0.50 (0.22, 0.87) | 1.4 | 4.6 |
| Plasma | Asp | 11 | 0.42 (0.22, 0.64) | 1.6 | 5.5 |
| Plasma | Pro | 15 | 0.26 (0.13, 0.36) | 2.7 | 8.9 |
| Plasma | Glu | 8 | 0.38 (0.27, 0.59) | 1.8 | 6.1 |
| Plasma | Phe | 14 | 0.30 (0.21, 0.40) | 2.3 | 7.7 |
| RBCs | Ala | 9 | 0.15 (0.11, 0.39) | 4.6 | 15.4 |
| RBCs | Val | 6 | 0.14 (0.05, 0.26) | 5.0 | 16.4 |
| RBCs | Leu | 7 | 0.12 (0.10, 0.52) | 5.8 | 19.2 |
| RBCs | Ser | 5 | 0.30 (0.24, 0.55) | 2.3 | 7.7 |
| RBCs | Asp | 8 | 0.18 (0.15, 0.35) | 3.8 | 12.3 |
| RBCs | Pro | 8 | 0.10 (0.07, 0.16) | 6.9 | 23.0 |
| RBCs | Glu | 8 | 0.20 (0.16, 0.27) | 3.5 | 11.5 |
| RBCs | Phe | 6 | 0.12 (0.06, 0.17) | 5.8 | 19.2 |
1
Estimated using nonlinear least squares. The number of converged models is out of 18 subjects. CIRAA, carbon isotope ratio of amino acid.
2
Units of λ, the fractional incorporation rate, are week−1.
3
Median weeks until 50% turnover (half-life) and 90% turnover calculated as tx = −ln (1 − x)/λ.