Intravital Video Microscopy of Forelimb Capillary Blood Flow in Rat Skeletal Muscle
Bibliographic record
Abstract
Objective The present study describes the development of a novel in vivo microvascular preparation for the investigation of capillary blood flow in the extensor carpi radialis longus (ECRL) muscle of rat. Blood flow measurements in the forelimb provide an alternative to other contemporary vascular preparations and is particularly useful for investigating capillary blood flow in disease models where hind limb flow is impaired (e.g. hind limb unloading, reduced uterine perfusion pressure etc.). Methods Two male Sprague‐Dawley rats, 174 and 161g were anaesthetized with pentobarbital, tracheotomized, ventilated, and maintained in a normotensive state via minimal saline infusion in the jugular vein. The skin on the lateral side of the right forelimb was removed exposing the muscle capsule surrounding the extensor carpi radialis longus and brevis muscles. The distal tendon of the ECRL was secured with a silk ligature and the muscle was carefully isolated and reflected onto an inverted microscope stage. The muscle was bathed in warm saline and isolated from the air via polyvinylidene chloride film and a glass coverslip. Ten – twenty, 1 minute video sequences of capillary blood flow at 20X magnification were recorded in each animal. Videos were analyzed offline using custom software written in MATLAB yielding frame‐by‐frame measurements of capillary hemodynamics and oxygen saturation. Results Capillary measurements were made in a total of 69 vessels (31 ‐ 38 in each animal), with erythrocyte velocities of 196.8±40.2 μm/s; tube hematocrit 19.9±2.9 %; 10.7±0.7 cells/s; and entrance and exit oxygen saturation of 70.4±5.6 % and 55.8±4.6% respectively. Conclusions We demonstrate direct measurement of microvascular hemodynamics and capillary oxygen saturation in a novel intravital preparation using rat ECRL muscle.
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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".