Amino Acid Transport Kinetics and Protein Turnover in Hemodialysis
Bibliographic record
Abstract
Background: Protein metabolism is abnormal in patients with end-stage renal disease. However, the etiology of abnormal protein turnover is unclear. Also the role of hemodialysis on protein turnover remains controversial. Abnormal protein metabolism could be due to malnutrition or due to abnormal amino acid transport kinetics Hypothesis: 1) Amino acid transport is abnormal in uremia, 2) Hemodialysis increases fractional protein synthesis rate and c) Net protein accretion is negative during hemodialysis because of increased catabolism. Aim: 1) To study the impact of uremia and hemodialysis on intracellular amino acid transport kinetics and 2) Quantify the fractional protein synthesis rate and degradation in a uremic state and during hemodialysis Methods: Protein turnover and amino acid transport kinetics using stable isotopes of phenylalanine in 2 patients and 2 controls. The patients were placed on a standard diet (1.2 gm/Kg protein and 35 Kcal/Kg) for 2 weeks prior to the study. Acidosis as corrected by NaHCO3 supplementation. Amino acid transport and protein turnover were estimated by compartmental model and precursor product approach respectively. Results: Mean protein intake and HCO3 were 1.4 ± 1 gm/day and 26.8 ± 4.1 meq/L respectively. Inward transport (11.2 ± 2.6 vs. 9.8 ± 2.1 nmol/min−1/100 ml leg−1) and outward transport (10.2 ± 1.2 vs.11.0 ± 1.6 l nmol/min−1/100 ml leg−1) were not different before and during HD. Inward and outward transport in controls were 12.6 ± 3.7 and 16.2 ± 3.5 nmol/min−1/100 ml leg−1 respectively. Protein synthesis was higher than catabolism in the pre-dialysis phase (156.8 ± 66.1 vs. 144.3 ± 53.7 nmol/min/ml leg-1, p = NS), but catabolism was higher than synthesis during HD (172.3 ± 20.5 vs. 186.8 ± 25.8 nmol/min/ml leg-1, p = NS). Protein synthesis and catabolism in controls were 110.8 ± 13.5 and 127.4 ± 12.7 nmol/min/ml leg-1. Conclusion: 1. Inward and outward transport of amino acids are not altered by renal failure or hemodialysis. 2. Protein turnover is increased during hemodialysis, with net balance favoring catabolism
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".