Contractile function in myocytes from aged hearts is altered with glucose compared to fat as the substrate (1154.7)
Bibliographic record
Abstract
Substrate utilization generally favors fatty acid oxidation over glucose utilization in normal healthy hearts. Aging is associated with attenuated myocardial contractile function; however age related changes in substrate utilization are less understood. Most studies of metabolic aspects on cardiac function have been done in whole hearts and little information is available about cellular contractile responses in the presence of different substrates. We determined substrate effects on contractile properties in isolated myocytes from young (6 months) and old (33 months) FBN rats. We measured percent shortening and rate of shortening at time 0 (T0) and after 10 minutes (T10) of continuous stimulation at 2 Hz in myocytes isolated from healthy hearts and bathed in Ringers solution containing either 11mM glucose (G) or 0.4 mM oleate (O). Both percent shortening and rate of shortening at T10 were lower than at T0 regardless of age or substrate. However, in old myocytes there was a significantly (p < 0.05) larger decrease over time (∆ = T10 ‐ T0) when G (∆ % shortening = ‐2.87) was the substrate compared to O (∆ % shortening = ‐1.37). In young myocytes there were no substrate differences (∆ % shortening = ‐1.36 and ‐1.42 in G and O, respectively). Similar results were seen with the rate of shortening. These data suggest that aging results in altered substrate utilization that affects myocyte contractile properties. Grant Funding Source : Supported by NIH AG 030423
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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 | 0.001 | 0.000 |
| 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) | 0.003 | 0.001 |
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".