Regional reduction in excitability and connexin 43 expression in areas of conduction disturbance in canine ventricles with chronic rapid pacing and ameroid constrictor
Bibliographic record
Abstract
It has been suggested that altered connexin43 (Cx43) expression may be associated with reentrant ventricular arrhythmias in chronic myocardial infarction. A similar possibility was investigated in canine hearts without necrotic scar, which were subjected to chronic rapid pacing (CRP) at 240 beats/min for 4 weeks and progressive obliteration of the left coronary circumflex artery (LCx) by an ameroid constrictor. Electrophysiologic alterations identified by mapping the LCx territory (191 unipolar recordings) included activation delay, ST segment potential elevation and reduced maximum negative slope (−dV/dtmax) in the activation complex of unipolar electrograms. The LCx was divided into areas displaying depressed conduction (LCx1: 0.07±0.04 m/s,mean±SD) and milder depression (LCx2: 0.23 ±0.01 m/s). Cx43 measured by Western blot in tissue sampled from LCx1 was significantly reduced (62±63%) but not in LCx2 (39±87%) with reference to the left anterior descending artery territory (100%). Moreover, ‐dV/dtmax was significantly depressed (5.3±3.6 mV/ms) and ST segment potential was significantly elevated (17.7±17 mV) in LCx1 in comparison with LCx2 (10±3.9 mV/ms and −1.1±1.9 mV, respectively). The data indicate that conduction disturbances are induced by reduced Cx43 expression in conjunction with depressed excitability in viable energy‐stressed myocardium. Supported by the Canadian Institutes of Health Research and Quebec Heart Foundation.
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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) | 0.000 | 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) | 0.001 | 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".