Thebesian sinusoids: forgotten collaterals to papillary muscles.
Bibliographic record
Abstract
BACKGROUND: Papillary muscles of the left ventricle are prone to ischemic damage but seldom rupture, perhaps because they are protected by transendocardial diffusion and thebesian sinusoids as well as by arteries. Sinusoids are primitive vessels that precede coronary arteries as nutrient suppliers to all parts of the embryonic heart. OBJECTIVES: To determine whether sinusoids penetrate to the tips of papillary muscles. MATERIALS AND METHODS: Adult hearts with and without evidence of acute and chronic ischemic lesions were selected. Papillary muscle sinusoids were perfused by black ink from the apex of the left ventricle. Papillary muscles and the adjacent ventricular free walls were then excised and fixed before gross and microscopic examination for inked sinusoids. Some fixed specimens were cleared through methyl salicylate and examined stereoscopically. RESULTS: The meshwork of trabeculae and, importantly, intertrabecular spaces lining the apex of the left ventricle continue into the deeply undercut bases of papillary muscles. In most hearts, sinusoids can be shown to extend from the undercut bases to the tips of human papillary muscles, especially in ischemic hearts. The compact myocardium of the adjacent ventricular free wall contains few sinusoids. CONCLUSIONS: Sinusoids may supplement normal arterial flow to papillary muscles and mitigate the effects of coronary occlusion. The authors hypothesize that the apex of the human left ventricle is adapted for sinusoidal flow to papillary muscles.
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 | 0.001 |
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".