Mechanisms of ischemic preconditioning effects on Ca<sup>2+</sup>paradox-induced changes in heart
Bibliographic record
Abstract
The effects of ischemic preconditioning (IP) on changes in cardiac performance and sarcoplasmic reticulum (SR) function due to Ca 2+ paradox were investigated. Isolated perfused hearts were subjected to IP (three cycles of 3-min ischemia and 3-min reperfusion) followed by Ca 2+ -free perfusion and reperfusion (Ca 2+ paradox). Perfusion of hearts with Ca 2+ -free medium for 5 min followed by reperfusion with Ca 2+ -containing medium for 30 min resulted in a dramatic decrease in the left ventricular (LV) developed pressure and a marked increase in LV end-diastolic pressure. Alterations in cardiac contractile activity due to Ca 2+ paradox were associated with depressed SR Ca 2+ -uptake, Ca 2+ -pump ATPase, and Ca 2+ -release activities as well as decreased SR protein contents for Ca 2+ -pump and Ca 2+ channels. All these changes due to Ca 2+ paradox were significantly prevented in hearts subjected to IP. The protective effects of IP on Ca 2+ paradox changes in cardiac contractile activity as well as SR Ca 2+ -pump and Ca 2+ -release activities were lost when the hearts were treated with 8-( p-sulfophenyl)-theophylline, an adenosine receptor antagonist; KN-93, a specific Ca 2+ /calmodulin-dependent protein kinase II (CaMK II) inhibitor; or chelerythrine chloride, a protein kinase C (PKC) inhibitor. These results indicate that IP rendered cardioprotection by preventing a depression in SR function in Ca 2+ paradox hearts. Furthermore, these beneficial effects of IP may partly be mediated by adenosine receptors, PKC, and CaMK II.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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) | 0.000 | 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 teacher head, 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".