Abstract:
La présente invention concerne une méthode de calibration universelle utile pour le dosage des inhibiteurs d'une même enzyme, par exemple pour le dosage des inhibiteurs d'une enzyme de la coagulation sanguine. L'invention concerne également l'utilisation de cette calibration universelle dans une méthode de dosage d'un inhibiteur réversible ou irréversible de l'enzyme, dans un échantillon biologique. L'invention concerne aussi l'utilisation de la calibration universelle dans une méthode de criblages d'inhibiteurs de l'enzyme.
Abstract:
Provided are compositions and methods for accurate determination of the concentration of anticoagulant in a sample such as a blood or plasma sample. The compositions can contain a Factor X compound and Factor V compound, and additional components as well. Methods for performing the assay include one-step methods in which a sample is added to a coagulation assay composition, and time is monitored from the point of adding the sample and coagulation assay composition to an endpoint, such as clot formation.
Abstract:
A chromogenic assay for determination of blood coagulation Factor IX (christmas factor) utilizes Factor Xa formed by the conversion of Factor X by activated Factor IX to cleave a chromogenic substrate. Conversion of Factor X to Factor Xa is coupled to a Factor XI mediated conversion to Factor IXa in a substantially two step procedure.
Abstract:
Tripeptidic derivatives having the following formula: (FORMULA) wherein R s is a substituted chromogen group which may be splitted up by enzymatic hydrolysis with the formation of a splitted coloured or fluorescent product H - R s. The tripeptidic derivatives having the formula 1 are used for determining enzymes, particularly of the Xa factor. The enzyme material is reacted with said tripeptidic derivatives. The quantity of the scission product H - R s obtained from the action of the enzyme on the tripeptidic derivatives is determined by photometry, spectrophotometry, spectrophotofluorescence or electrochemistry. The amount of the splitted product H - R s released is proportionnel to the amount of enzymes contained in the starting material.
Abstract:
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.
Abstract:
The invention relates to a method for identifying blood clotting, in particular, blood clotting that is triggered by the intravascular tissue factor (TF). The inventive method involves the following steps: collecting a whole blood sample; stabilizing the whole blood sample by adding an anticoagulant substance; adding at least one constituent to the extracellular matrix; adding an inhibitor that inhibits contact activation; adding factor VIIa(i), and; detecting the blood clotting using a customary method.
Abstract:
The invention relates to a method of monitoring the effect of a direct of indirect Factor Xa inhibitors comprising the steps of collecting a plasma sample from a patient, adding a solution of Russell's viper venom to the plasma sample and measuring the clotting time or the residual FXa activity chromogenically.
Abstract:
The present invention provides a method for functionally classifying a protein that is capable of unfolding due to a thermal change. The method comprises screening one or more of a multiplicity of different molecules for their ability to shift the thermal unfolding curve of the protein, wherein a shift in the thermal unfolding curve indicates that the molecule binds to the protein or affects the stability in a measurable way; generating an activity spectrum for the protein wherein the activity spectrum reflects a set of molecules, from the multiplicity of molecules, that shift the thermal unfolding curve, of the protein and therefore are ligands that bind to the protein, comparing the activity spectrum for the protein to one or more functional reference spectrum lists; and classifying the protein according to the set of molecules in the multiplicity of different molecules that shift the thermal unfolding curve of the protein.
Abstract:
Method of determining the heparin content, which method comprises the following steps: (a) adding a known amount of thrombin (FIIa) or activated coagulation factor X (FXa) to a mixture which comprises a known concentration of chromogenic substrate (S), a known concentration of antithrombin (AT) and a sample having an unknown heparin concentration, the amount of FIIa or FXa being chosen such that at most 20 %, preferably at most 10 %, of the S present is reacted during the period which the AT needs to deactivate all the FIIa or FXa present, (b) allowing the reactions which occur to proceed and determining the final concentration of the reacted chromogenic substrate ([pNA]final) after completion of the reactions, (c) using the [pNA]final found to determine the rate constant (kdec) of the reaction of FIIa or FXa with AT, and (d) determining the heparin concentration in the sample using the value of kdec thus found from a predetermined calibration curve of kdec against heparin concentration.