Porcine mucosal Heparin (mean molecular weight= 15.000 Dalton) has been chemically depolymerized in presence of peroxides and N-sulphate groups have been re-introduced by reaction with sulpho- trioxides of amines. The depolymerization has been stopped at different times and the products are essayed for Anti-Xa, APTT and their ratio. A rise in the ratio Anti-Xa/APTT has been observed.In order to check for an activity on the platelet aggregation, two sets of experiments have been carried out: in a first model, the 5-hydroxytrip- tamine (5-HT) release has been measured after addition of different quantities of products to washed platelets. One commercil Heparin gave a significant rise in 5-HT release whereas a normal porcine mucosal Heparin did not show any modification in basal values, nor significant modifications have been observed for low molecular weight heparins (10.000 to 7.000 D). Heparansulphate (HS) and Dermatansulphate (DS) show a slight anti-aggregating activity in this test.In a second model, the percentage inhibition in collagen induced platelet release has been measured in a platelet rich plasma (PRP). All the tested heparins show a very significant inhibition, whereas HS and DS have no inhibiting activity in this test.
