Comparative specificity of platelet alpha(IIb)beta(3) integrin antagonists.
Bibliographic record
Abstract
Several platelet alpha(IIb)beta(3) integrin antagonists have been designed as preventive agents against the formation of arterial thrombi. Although the potency of these compounds in inhibiting platelet aggregation is in the nanomolar range, their specificity on other integrins that can bind ligands through an arginine-glycine-aspartic acid (RGD) motif is far from being well established. For instance, some cyclic RGD peptides can also interact with alpha(v)beta(3) integrin. We used a novel pharmacological assay, based on SDS-stable interaction between (125)I-echistatin and RGD-dependent integrins, to evaluate the specificity of several RGD compounds on integrins present on rat cardiac fibroblasts and human skin fibroblasts. None of the RGD peptidomimetics tested (L-734,217, lamifiban, Ro 44-3888, SR 121566A, BIBU-52, XV459) could interact with either alpha(v)beta(3) and alpha(8)beta(1) on rat fibroblasts or with alpha(v)beta(3) and alpha(v)beta(1) on human fibroblasts. Cyclic RGD peptides showed some potency (3-80 microM) on rat and human integrins with an alpha(v) subunit. We also compared the potency of these compounds on platelets. All RGD compounds demonstrated IC(50) between 0.6 and 530 nM on basal human platelets. Activation of the receptor with thrombin resulted in a 2- to 60-fold increase in potency, with L-734,217 and BIBU-52 showing the largest difference. On basal and thrombin-activated rat platelets, only eptifibatide, DMP728, and XJ735 could displace (125)I-echistatin (IC(50) approximately 0.1-1.5 microM). These results indicate that RGD peptidomimetics have a specificity limited to alpha(IIb)beta(3) integrin, whereas cyclic RGD peptides can also interact with other RGD-dependent integrins, particularly those of the alpha(v) subunit family.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 teacher head, 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".