Glycemia and the cardioprotective effects of insulin pre-conditioning in the isolated rat heart
Bibliographic record
Abstract
BACKGROUND: While acute hyperglycemia has been shown to mitigate the beneficial effects of ischemic preconditioning, its effect on insulin-induced preconditioning remains unclear. METHODS: The study was designed to test the hypothesis that acute hyperglycemia diminishes the cardioprotective effects following a 20-min pre-ischemic pre-conditioning with insulin in the isolated rat heart using the Langendorff system. Forty hearts were assigned to receive modified Krebs-Henseleit (KH) buffer containing 0.5 U/L insulin and 100 mg/dL glucose (InsG100, n = 10), KH buffer with 100 mg/dL glucose (G100, n = 10), KH buffer supplemented with 0.5 U/L insulin and 600 mg/dL glucose (InsG600, n = 10), or with 600 mg/dL glucose (G600, n = 10). To match the osmotic pressure of the InsG600 group, 27.5 mmol/L of mannitol was added to KH solution in the InsG100 and G100 group. The four groups were perfused with each solution for 20 min prior to 15 min of no-flow ischemia, and during 20 min of reperfusion. Only during the ischemic period the heart was paced at 222 beats/min. Measurements of heart rate, coronary flow and maximum of LV derivative of pressure development (dP/dt max) were recorded. Myocardial phospho-protein kinase B (p-Akt) and tumor necrosis factor-α (TNF-α) levels were assayed by enzyme-linked immunosorbent assay and sandwich ELISA, respectively following reperfusion. RESULTS: After reperfusion, LV dP/dt max and heart rate in the InsG100 group was significantly higher than that in the other three groups. The myocardial p-Akt level in the InsG100 group was significantly elevated when compared to the InsG600 group at the end of reperfusion. The p-Akt levels in the InsG600 and InsG100 group were significantly higher than in the corresponding non-insulin groups. CONCLUSIONS: Acute hyperglycemia diminishes the cardioprotective effects of insulin preconditioning in the isolated rat heart, possibly mediated through the suppression of myocardial Akt phosphorylation.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".