Disappearance of human platelet factor 4 (PF4) in rabbits: does an immediate component exist?

@article{Prosdocimi1985DisappearanceOH,
  title={Disappearance of human platelet factor 4 (PF4) in rabbits: does an immediate component exist?},
  author={Marco Prosdocimi and Novella Scattolo and A. Mazzucato and Alberto Zatta and Fabrizio Fabris and Antonio Girolami and Giuseppe Cella},
  journal={Thrombosis research},
  year={1985},
  volume={39 5},
  pages={
          541-7
        }
}
3 Citations
Kinetics of Human Platelet Factor 4 in Rabbits Effect of Glycosaminoglycans and Protamine Sulfate
TLDR
It is observed that human platelet factor 4 is rapidly cleared with a biphasic curve, with an initial fast component followed by a slower disappearance, and this findings are consistent with two different lots of heparin-agarose purified PF4 and crude material released by platelets, although some difference may exist.
Human platelet factor 4 and protamine sulphate interaction with glycosaminoglycans in the rabbit
TLDR
Although part of the protamine will displace PF4 from the binding sites of the dermatan sulphate molecule, the remaining part of protamine could probably be bound to this GAG without losing its activity so that, upon subsequent heparin injection, it is immediately neutralized, rendering it unavailable for further PF4 harvesting.

References

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Clearance and in vivo release by heparin of human platelet factor 4 (PF4) in the rabbit.
TLDR
13 male New Zealand rabbits were injected with two different doses of human platelet factor 4 antigen (PF4) and the disappearance of the protein was extremely fast with an half-life for the fast component and its clearance from plasma was slow.
Effect of heparin on the in vivo release and clearance of human platelet factor 4.
TLDR
It is proposed that PF4 is originally secreted by platelets into circulation and subsequently bound reversibly to vascular sites from which it can be released back into the circulation by heparin.
Purification and binding properties of human platelet factor four.
Plasma heparin: a unique, practical, submicrogram-sensitive assay.
TLDR
The assay is based on the original observation of the accelerating effect of trace amounts of heparin on the neutralization of activated factor X by its plasma inhibitor and has both a specificity and a sensitivity greater than those of the whole blood clotting time or the activated partial thromboplastin time.