Inhibitors of Platelet Aggregation from Diverse Haematophagous and Predaceous Hirudinea from around the World.
Bibliographic record
Abstract
Abstract Introduction Haematophages, animals evolved to a blood sucking lifestyle as their exclusive mode of feeding secrete compounds capable of arresting haemostasis in the host. Since the discovery and subsequent characterisation and engineering of hirudin, attention is being focused on the potential anticoagulant and platelet aggregation inhibitors from an array of different species of leech from both the Rhynchobdellid and Arhynchobdellid orders. The purpose of this study was to survey the presence of inhibitors of platelet aggregation in cephalic extracts prepared from phylogenetically diverse proboscis-bearing and jawed blood-sucking leeches compared to those which are predaceous in nature. Methods Cephalic extracts from specimens of each species were prepared by homogenising in tris buffer the anterior one-third region of the bodies containing the salivary glands. In the case of the giant leech, Haementeria ghilianii, paired anterior salivary glands were excised through the oesophagus. The posterior musculature served as control material. Homogenates were double centrifuged and supernatants micro-filtered. Individual extracts or imidazole buffer as control were pre-incubated 1:4 with platelet rich plasma for 5 minutes prior to testing for inhibition of platelet aggregation. Inducers of aggregation were: ADP (5 and 10 μM/ml), Collagen (COL) (4μg/ml), Thrombin (THR) (0.2 U/ml), Ristocetin (RIS) (1.5 mg/ml) and Adrenaline (ADR) (1 μM). Maximal aggregation responses were measured over 10 minutes. All extracts were kept on ice and tested within 1 hour of preparation. Results The species of leeches examined and maximal aggregation responses (%) after 10 minutes are shown in table 1. Maximal Responses (%) to Aggregation Inducers in Haematophagous and Predaceous Leeches Species Source ADP COL THR RIS ADR Haematophagus Haementeria ghilianii Brazil <10 <10 <10 <10 <10 Oothuizobdell garoui South Africa <10 <10 <10 20 15 Placobdella parasitica Canada 10 10 <10 15 20 Hirudinaria manillensis China <10 <10 <10 <10 <10 Macrobdella decora North America <10 <10 <10 <10 <10 Hirudinaria javanica Indonesia <10 <10 <10 <10 <10 Poecilobdella granulose India <10 <10 <10 <10 <10 Myxobdella Africana Kenya 15 20 <10 20 25 Hirudo medicinalis Turkey <10 <10 <10 <10 <10 Predaceous Haemopis sanguisuga UK 100 100 100 100 100 Helobdella stagnalis UK 90 90 95 100 100 Erpobdella octoculata UK 100 95 95 100 100 Glossiphonia complanata UK 100 100 100 100 100 None of the extracts induced the spontaneous aggregation of platelets suspended in autologous plasma. Posterior musculatures did not inhibit platelet aggregation. Conclusion Cephalic extracts from all the haematophagous leeches examined in this study contain inhibitors of platelet aggregation. Our findings suggest that anti-haemostatic properties in Hirudinea appear to have evolved in response to biological adaptations rather than in keeping with phylogenetic affinities. Further work is required to define the precise nature of such mechanisms. These new anti-platelet properties in different species could have further potential therapeutic applications.
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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) | 0.000 | 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".