ESCA studies on heparin-like materials used for extracorporeal shunts.

Amino-acids sulfamide substituted polystyrene surfaces exhibit an heparin-like activity. Similar treatments were achieved on small diameter tubings made of polystyrene grafted on polyethylene. Electron spectroscopy for Chemical Analysis (ESCA) appeared as the suitable method for a chemical characterization of the surface (approximately 50-100 A depth) to be in contact with circulating blood. These tubings were implanted as extracorporeal shunts on dogs. The variations of local concentrations of labelled platelets, red cells and fibrinogen were recorded in situ. Depending on the conditions of preparation and implantation, a slight adhesion of platelet was observed. By using such type of materials with an improved mechanical compliance, small diameter antithrombogenic tubings could be developed, provided the chlorosulfonation prior to amino-acid grafting is mild.

Fast atom bombardment mass spectra of various peptides from sarcoplasmic calcium-binding protein.

The sarcoplasmic calcium-binding protein of the crayfish Astacus leptodactylus is a calciprotein. The primary structure of this protein has been determined. Tryptic digestion of the denaturated protein followed by high-performance liquid chromatographic separation identified essentially eight peptides. The structure of these peptides has been confirmed after amino acid analysis by fast atom bombardment spectra in positive mode.