Isolation and Characterization of Atrioventricular Nodal Cells From Neonate Rabbit Heart
Bibliographic record
Abstract
BACKGROUND: The properties of the atrioventricular (AV) node in the neonate heart and its role in unique pediatric cardiac arrhythmias such as junctional ectopic tachycardia (JET) are poorly understood. This is due in large part to the dearth of information on the structure and physiology of the AV node in the immature myocardium. METHODS AND RESULTS: Sinoatrial nodal cells (SANCs), AV nodal tissues, and myocytes (AVNCs) were obtained from neonatal (10-day-old) rabbits, and the histological, immunohistological, and electrophysiological properties were characterized in detail. Masson's trichrome histological staining clearly delineated AV nodal structures including the inferior nodal extension, compact node, and the bundle of His region. AV tissue sections and AVNCs were immunolabeled against neurofilament 160 (NF160), connexin 43 (Cx43), hyperpolarization-activated, cyclic nucleotide modulated channel (HCN4), sodium/calcium exchanger, ryanodine receptor, sarcoplasmic/endoplasmic reticulum Ca(2+) pump (SERCA), and phospholamban (PLB). In AVNCs with triple-positive NF160, SERCA, and PLB labeling, SERCA and PLB were found with high degrees of colocalization. The majority (59%) of NF160-positive AVNCs were found to coexpress HCN4. NF160 and HCN4 expression was found to be even higher in SANCs, where 88% of SANCs exhibited coexpression. Spontaneous action potentials recorded from isolated neonatal AVNCs were uniformly of the atrionodal type, showing none of the action potential heterogeneities found in the mature heart. Current recordings found the hyperpolarization-activated funny current (I(f)) in 55% (11 of 21 cells) of AVNCs, consistent with the immunocytochemistry results. CONCLUSIONS: This represents the first detailed electrophysiological and immunohistological report of the neonatal AV node and lays the groundwork for a better understanding of heart rate regulation and unique arrhythmias in the neonate heart.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
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".