The present disclosure relates to an assay that measures the level of factor Xa inhibitors in a sample by detecting residual factor Xa activity. In particular, the assay utilizes a mutant variant of prothrombin that lacks proteolytic activity; a prothrombinase complex mixture; and a thrombin-specific inhibitor and measures the factor Xa activity.

The present invention relates to a universal calibration method of use for assaying inhibitors of the same enzyme, for example for assaying inhibitors of an enzyme of blood coagulation. The invention also relates to the use of this universal calibration in a method for assaying a reversible or irreversible inhibitor of the enzyme in a biological sample. The invention also relates to the use of the universal calibration in a method for screening inhibitors of the enzyme.

The invention provides peptides that bind Tissue Factor Pathway Inhibitor (TFPI), including TFPI-inhibitory peptides, and compositions thereof. The peptides may be used to inhibit a TFPI, enhance thrombin formation in a clotting factor-deficient subject, increase blood clot formation in a subject, treat a blood coagulation disorder in a subject, purify TFPI, an identify a TFPI-binding compound.

The measurement of Factor Xa (FXa) enzymatic activity using novel fluorogenic peptide substrates that have a C-terminus cleavable fluorophore and optionally the ability to attach to a solid support. Fluorogenic measurements increase sensitivity and flexibility of measurements of enzymatic reactions over traditional absorbance-based approaches. The measurement of FXa generation is applicable to a range of biological reactions.

The present invention provides a method of identifying a coagulation inhibitor in a sample, comprising: a) contacting a first portion of the sample with a substrate and thrombin; b) contacting a second portion of the sample with a substrate and a2M-thrombin (thrombin caged in alpha-2-macroglobulin); c) contacting a third portion of the sample with a substrate and coagulation factor Xa; d) contacting a fourth portion of the sample with a substrate and a2M-Xa (factor Xa caged in alpha-2-macroglobulin); and e) assaying for cleavage of the substrate in (a), (b), (c) and (d) above, wherein cleavage of the substrate in (b) and (d) and no cleavage in (a) and (c) identifies heparin in the sample; cleavage of the substrate in (a), (b) and (d) and no cleavage in (c) identifies low molecular weight heparin in the sample; cleavage of the substrate in (a) and (b) and no cleavage in (c) and (d) identifies rivaroxaban in the sample, and cleavage of the substrate in (c) and (d) and no cleavage in (a) and (b) identifies dabigatran in the sample.

The present invention relates to a method for detecting at least one direct factor Xa inhibitor in a sample other than citrate plasma, comprising the step of mixing a sample containing a factor Xa inhibitor with a composition containing factor Xa under conditions which allow the factor Xa to release a detectable substance from a chromogenic substrate.

Compositions and methods diagnose and/or treat chronic kidney disease (CKD) using one or more feline circulating proteins as markers for early-stage CKD. A method of diagnosing chronic kidney disease (CKD) in a feline can include measuring an amount of each of at least one circulating protein from the feline. The at least one circulating protein is one or more of adiponectin (ADIPOQ), cathelicidin (CAMP), kinesin-like protein (KIF12), plasma retinol-binding protein (RBP4), Ig-like domain-containing protein (ZKSCAN1), coagulation factor X (F10), fibronectin (FN1) and mixtures thereof. The method also includes performing comparison of the amount of each of the at least one circulating protein from the feline to a corresponding predetermined value or a corresponding predetermined range. The method also includes diagnosing the feline as having early-stage CKD or not having early-stage CKD, based on the comparison.

The invention provides peptides that bind Tissue Factor Pathway Inhibitor (TFPI), including TFPI-inhibitory peptides, and compositions thereof. The peptides may be used to inhibit a TFPI, enhance thrombin formation in a clotting factor-deficient subject, increase blood clot formation in a subject, treat a blood coagulation disorder in a subject, purify TFPI, an identify a TFPI-binding compound.

The invention provides peptides that bind Tissue Factor Pathway Inhibitor (TFPI), including TFPI-inhibitory peptides, and compositions thereof. The peptides may be used to inhibit a TFPI, enhance thrombin formation in a clotting factor-deficient subject, increase blood clot formation in a subject, treat a blood coagulation disorder in a subject, purify TFPI, and identify a TFPI-binding compound.

The present invention relates to novel compounds suitable for the detection and/or inhibition of coagulation proteases, specifically APC, fIIa, fXa, and fXIa. The compounds have the structural formula 1 or X shown below:

##STR00001## in which R.sub.1, P.sub.1, P.sub.2, P.sub.3, P.sub.4, Z, R.sub.1x, A.sub.1, A.sub.2, A.sub.3, A.sub.4 and Z.sub.x are defined herein.

The present invention also relates to compositions comprising the compounds of formula I or formula X defined herein, to processes for synthesising these compounds and to their use for the treatment and/or detection of diseases and conditions in which coagulation proteases, in particular APC, fIIa, fXa, and fXIa, are implicated.