title: Effect of hydroxyethyl starch on the structure of thrombin- and reptilase-induced fibrin gels.
abstract: The effect of hydroxyethyl starch (HES), a complex polysaccharide colloid plasma expander, on the structure of fibrin gels was studied turbidimetrically. HES at concentrations as low as 2.5 mg/ml shortened the lag phase of turbidity increase and caused increased fibrin fiber mass/length ratios in both purified fibrin and plasma systems. For purified fibrin gels clotted with thrombin the mass/length ratio increased in a linear fashion from 2.6 to 6.1 X 10(12) daltons/cm as HES increased from 0 to 15 mg/ml. Fiber mass/length ratios for purified fibrin gels clotted with reptilase increased from 1.1 to 6.4 X 10(12) daltons/cm over the same HES concentration range. The addition of 5 mmol/L calcium to either system produced additional increases in fiber size. In 1:10 dilutions of plasma, HES shortened the lag phase, enhanced the rate of turbidity increase, and increased the final gel turbidity. The fiber mass/length ratio for plasma gels clotted with thrombin increased from 0.3 to 1.7 X 10(12) daltons/cm as HES increased from 0 to 20 mg/ml. For plasma gels clotted with reptilase, the fiber mass/length ratio increased from 1.5 to 2.4 X 10(12) daltons/cm over the same HES concentration range. The effects of HES are comparable to those of dextran at concentrations less than 5 mg/ml and can be explained on the basis of HES-enhanced lateral association of fibrin fibers during polymerization.
mesh_terms: D012103:Batroxobin / Q000378:metabolism*; D005337:Fibrin / Q000378:metabolism*; D005782:Gels; D006801:Humans; D006895:Hydroxyethyl Starch Derivatives / Q000494:pharmacology*; D007700:Kinetics; D009391:Nephelometry and Turbidimetry; D010447:Peptide Hydrolases / Q000378:metabolism*; D013213:Starch / Q000031:analogs & derivatives*; D013917:Thrombin / Q000378:metabolism*
chemical_list: D005782:Gels; D006895:Hydroxyethyl Starch Derivatives; D005337:Fibrin; D013213:Starch; D010447:Peptide Hydrolases; D012103:Batroxobin; D013917:Thrombin