Development and clinical evaluation of two chromogenic substrate methods for monitoring fondaparinux sodium.

This study was designed to develop methods for monitoring of the selective factor Xa inhibitor fondaparinux sodium (ARIXTRA) based on standard laboratory methods for the chromogenic determination of the anti-factor Xa activity of low molecular weight heparin. To examine the biologic activity of fondaparinux in comparison to its plasma concentration, 2 methods were investigated: 1 working with the addition of antithrombin (AT), the other without exogenous AT. Both methods showed a linear relationship of fondaparinux concentration and OD/min on a log-lin scale in the range from 0.

Hirudin determination in plasma can be strongly influenced by the prothrombin level.

Recombinant hirudin is increasingly used for therapeutic and prophylactic anticoagulation. Several laboratory methods are available to measure r-hirudin, including clot-based and amidolytic methods. The snake venom ecarin converts prothrombin to meizothrombin.

The structure of the human betaII-tryptase tetramer: fo(u)r better or worse.

Tryptases, the predominant serine proteinases of human mast cells, have recently been implicated as mediators in the pathogenesis of allergic and inflammatory conditions, most notably asthma. Their distinguishing features, their activity as a heparin-stabilized tetramer and resistance to most proteinaceous inhibitors, are perfectly explained by the 3-A crystal structure of human betaII-tryptase in complex with 4-amidinophenylpyruvic acid. The tetramer consists of four quasiequivalent monomers arranged in a flat frame-like structure.

The three-dimensional structure of recombinant leech-derived tryptase inhibitor in complex with trypsin. Implications for the structure of human mast cell tryptase and its inhibition.

The x-ray crystal structure of recombinant leech-derived tryptase inhibitor (rLDTI) has been solved to a resolution of 1.9 A in complex with porcine trypsin. The nonclassical Kazal-type inhibitor exhibits the same overall architecture as that observed in solution and in rhodniin.

Purification, characterization and biological evaluation of recombinant leech-derived tryptase inhibitor (rLDTI) expressed at high level in the yeast Saccharomyces cerevisiae.

An efficient expression/purification procedure has been developed which allows the production of pure, biologically active recombinant leech-derived tryptase inhibitor (rLDTI), originally found in the leech Hirudo medicinalis. The gene for LDTI was generated synthetically from three overlapping oligonucleotides by PCR synthesis. LDTI was expressed in the yeast Saccharomyces cerevisiae under the control of the copper-inducible CUP1 promoter and fused to the invertase signal sequence (SUC2).