Repeated Doses of Oral and Subcutaneous Heparins Have Similar Antithrombotic Effects in a Rat Carotid Arterial Model of Thrombosis
Bibliographic record
Abstract
Although heparins are usually injected intravenously or subcutaneously, antithrombotic activity is observed in rat models following single oral heparin doses. Since repetitive dosing is usually needed for thromboprophylaxis, study objectives were to determine whether repetitive oral heparin prevented arterial thrombosis and to compare effectiveness to subcutaneous administration. Wistar rats were given subcutaneous or oral unfractionated heparin ([UFH] 1 mg/kg per 48 h), low-molecular-weight heparin ([LMWH] tinzaparin, 0.1 mg/kg per 12 h), or saline for 30 days. On the last day, thrombosis was initiated by placing 30% FeCl(3)-soaked filter paper on the distal carotid. Subsequent flow measurements, for a 60-minute period, included recorded time of initial thrombus formation (time till thrombus begins [TTB]), and time until carotid occlusion (time till occlusion [TTO]). The formed thrombus was dried and weighed. The activated partial thromboplastin time (aPTT), anti-factor Xa, and antithrombin activity were determined from the plasma. Both oral and subcutaneous heparins significantly increased TTB and TTO. Time of initial thrombus formations were 12.6 ± 1.1, 21.2 ± 2.2, 25.3 ± 3.9, 21.7 ± 3.1, and 21.3 ± 1.7 minutes and TTOs were 29.3 ± 3.6, 54.8 ± 4.0, 60.0 ± 0.3, 56.7 ± 3.3, and 58.3 ± 1.7 minutes (mean ± SEM) for control, subcutaneous UFH, oral UFH, subcutaneous LMWH, and oral LMWH, respectively. Thrombus weight was 2.52 ± 0.29 g in control and was reduced to 43%, 23%, 33%, and 28% of control weight for subcutaneous UFH, oral UFH, subcutaneous LMWH, and oral LMWH, respectively. Thrombus weight was significantly less for oral compared to subcutaneous UFH. The aPTT for oral UFH, and anti-factor Xa activity in the LMWH-treated groups were significantly greater than control (two-tailed t tests). These findings confirm that orally administered heparins are absorbed. Repeated treatment with oral heparin showed similar antithrombotic activity compared to subcutaneous heparin. Oral heparin use for arterial thromboprophylaxis should be further investigated.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 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".