Effect of Total Venous Occlusion on Capillary Flow and Necrosis in Skeletal Muscle
Bibliographic record
Abstract
Limb replantation and microvascular transfer of flaps are sometimes complicated by postoperative venous thrombosis. Total venous occlusion can lead to complete shutdown of microvascular perfusion, resulting in failure of the transfer or replantation. Once venous return stops, it must be restored within a critical period of time for tissue survival. The purpose of this experiment was to delineate this critical period of time at which no reflow and irreversible muscle necrosis occurs by the use of a rat gracilis flap microcirculation model. The gracilis muscle of 40 male Wistar rats (135.3 +/- 37.2 g) was elevated on its vascular pedicle and mounted on a raised platform for videomicroscopic analysis. Animals were randomly assigned to one of four groups: (1) sham (no total venous occlusion), (2) 10 minutes of total venous occlusion, (3) 30 minutes of total venous occlusion, and (4) 60 minutes of total venous occlusion. Total venous occlusion was established by placing a microvascular clamp across the femoral vein at the junction of the gracilis pedicle. The number of flowing capillaries in five consecutive high-power fields (832x) were counted at baseline and at 5, 15, 30, 60, 120, 180 minutes, and 24 hours after reperfusion. At 24 hours after reperfusion, the gracilis muscles were harvested and stained with nitroblue tetrazolium. Percentage of muscle necrosis was measured by using computer planimetry. The data were reported as mean +/- standard error of mean and were compared between groups by analysis of variance and appropriate post hoc comparisons. Total venous occlusion for 10, 30, and 60 minutes showed a significant decrease in the number of flowing capillaries through 24-hour postreversal. There was a significant drop (p < 0.01) in the number of flowing capillaries from 30 minutes of total venous occlusion to 60 minutes of total venous occlusion at all times. Muscle necrosis was significantly increased in all three groups of total venous occlusion compared with the sham group (36.1 +/- 1.7 percent, 45.5 +/- 3.4 percent, 74.1 +/- 4.7 percent versus 14.3 +/- 1.7 percent, and p < 0.01). These results indicate that irreversible tissue damage occurs in a very short time interval (60 minutes) in this model, making the early detection of venous occlusion critical to the successful correction of this complication.
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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".