Transmural pressure and membrane potential in human saphenous vein
Bibliographic record
Abstract
OBJECTIVE: An increase in transmural pressure reportedly depolarizes myocytes in various arterial blood vessels. We have examined the relationship between transmural pressure and membrane potential (E(m)) in human saphenous veins with a view to determine whether contractile force generation, hence spasmogenesis in vein grafts, involves a similar process of mechanoelectrical excitation. METHODS: Intracellular recordings were made by sharp glass microelectrodes in human isolated saphenous veins and parallel measurements were performed in ring preparations. RESULTS: E(m) values obtained in pressurized vessels at four different pressure levels were (mean+/-SD): -74.4+/-5.5 mV (0-6 cm H(2)O; n=10), -72.6+/-6.5 mV (11-14 cm H(2)O; n=27), -72.1+/-6.5 mV (26-27 cm H(2)O; n=30), and -72.9+/-4.0 mV (50-54 cm H(2)O; n=38), demonstrating the lack of an overt pressure-dependence. Except at the lowest transmural pressure tested, these values were significantly different from E(m) obtained in ring preparations (-77.8+/-4.0 mV; n=30). Raising extracellular K(+) to 80 mM produced a comparable depolarization in tissues either pressurized to 50-54 cm H(2)O (-64.9+/-4.3 mV; n=27) or set up as ring preparations (-64.06+/-6.9 mV; n=35). CONCLUSIONS: Human saphenous veins respond to transmural pressure with a limited depolarization that lacks correlation with pressure. The absence of a pressure-induced graded depolarization suggests that pressure-dependent vasoconstriction does not play a primary role in blood flow regulation in lower limb large veins. Moreover, this raises doubts that mechanical stimuli per se would lead to development of vasospasm in the early stages of saphenous vein grafting into arterial vascular beds.
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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 | 0.001 |
| 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".