Alternative pathways of thromboplastin-dependent activation of human factor X in plasma

Journal Article · Thu Jan 01 04:00:00 EST 1981 · Ann. N.Y. Acad. Sci.; (United States)

DOI:https://doi.org/10.1111/j.1749-6632.1981.tb29745.x· OSTI ID:5449138

Marlar, R A; Griffin, J H

To determine the interrelationships of the major coagulation pathways, the activation of 3H-labeled factor X in normal and various deficient human plasmas was evaluated when clotting was triggered by dilute rabbit or human thromboplastin. Various dilutions of thromboplastin and calcium were added to plasma samples containing 3H-factor X, and the time course of factor X activation was determined. At a 1/250 dilution of rabbit brain thromboplastin, the rate of factor X activation in plasmas deficient in factor VIII or factor IX was 10% of the activation rate of normal plasma or of factor XI deficient plasma. Reconstitution of the deficient plasmas with factors VIII or IX, respectively, reconstituted normal factor X activation. Similar results were obtained when various dilutions of human thromboplastin replaced the rabbit thromboplastin. From these plasma experiments, it is inferred that the dilute thromboplastin-dependent activation of factor X requires factors VII, IX, and VIII. An alternative extrinsic pathway that involves factors IX and VIII may be the physiologic extrinsic pathway and hence help to explain the consistent clinical observations of bleeding diatheses in patients deficient in factors IX or VIII.

• OSTI ID: 5449138
• Journal Information: Ann. N.Y. Acad. Sci.; (United States), Journal Name: Ann. N.Y. Acad. Sci.; (United States) Vol. 370; ISSN ANYAA
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
ALKALINE EARTH METALS
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL MATERIALS
BIOLOGICAL PATHWAYS
BLOOD
BLOOD COAGULATION
BLOOD COAGULATION FACTORS
BLOOD PLASMA
BODY FLUIDS
CALCIUM
COAGULANTS
DRUGS
ELEMENTS
HEMATOLOGIC AGENTS
HEMOSTATICS
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
MATERIALS
METALS
PHYSIOLOGY
REACTION KINETICS
THROMBOPLASTIN
TRITIUM COMPOUNDS