Studies in man and experimental animals of a low molecular weight heparin fraction.
In vitro and in vivo studies were carried out on a commercially prepared low molecular weight heparin fraction. By APTT assay the fraction had a specific activity of half that of unfractionated mucosal heparin, yet retained full potency by anti-Xa assay (both clotting and chromogenic substrate). When administered intravenously to human volunteers, the anti-Xa/APTT ratio remained the same as it was in vitro. However, after subcutaneous injection, the ratio increased and anti-Xa activity could not be fully neutralized ex vivo by PF4. The fraction was as effective as unfractionated heparin in preventing experimental serum-induced thrombosis, suggesting that a heparin fraction with high specific activity by anti-Factor Xa assay compared to APTT activity may be an effective drug for the prophylaxis of venous thrombosis.
D000328:Adult; D000368:Aged; D000818:Animals; D002850:Chromatography, Gel; D005753:Gastric Mucosa / Q000032:analysis; D006493:Heparin / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D007275:Injections, Intravenous; D007279:Injections, Subcutaneous; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D010314:Partial Thromboplastin Time; D011817:Rabbits
D006493:Heparin