Plasma blood coagulation factors
I. fibrinogen – protein, synthesized in liver, transforms into fibrin in course of blood coagulation. Fibrinogen is also essential for platelet aggregation, tissular reparation. Normal values into blood – 2-4 g/l (minimal level – 0,8 g/l). One can meet hypo- and hyperfibrinogenemy.
II. prothrombin – glycoprotein, synthesized in liver at vitamin K presence. Prothrombin transforms in fibrin under prothrombinase. Norma: 0,1-0,15 g/l. Minimal level – 40%. One can tell about hypo- and hyperprothrombinemia.
III. thromboplastin – consists of protein apoprothein III and phospholipid complex. It is in membrane structure of many tissues. It represents matrix for prothrombinase formation on external way.
IV. calcium – is essential for prothrombinase production, platelet aggregation, releasing and retraction reactions. Under norma: 0,03-0,04 g/l. Blood coagulation process remains normal until calcium level reducing to fits development.
V. accelerator-globulin – protein, synthesized in liver, is activated by thrombin, is in prothrombinase complex composition. Norma – up to 0,01 g/l. Minimal level -10-15%. Owren’s disease or parahemophily occurs at its absence.
VII. proconvertin – glycoprotein, vit K is essential for its synthesis, is synthesized in liver. Participates in prothrombinase formation on external way. Norma: about 0,005 g/l, minimal level – 5-10%. Alexander’s disease or parahemophilia occurs at its absence.
VIII. antihemophilic globulin (AHG) – glycoprotein, it is formed in liver, spleen, vascular wall. It is essential for prothrombinase formation on internal way. It forms complex with FW in plasma. Norma: 0,01-0,02 g/l. Minimal level – 30-35%. Hemophilia A appears at its absence or strong reducing of its concentration.
IX. Cristmas’ factor, antihaemophilic factor B – glycoprotein, is formed in liver at vit K presence, takes part in prothrombinase formation on internal way. Norma: 0,003 g/l. Minimal level- 20-30%. Hemophilia B (Christmas’ disease) is developed at its absence or strong reducing of its concentration.
X. Stuart-Prawer’s factor - glycoprotein, is formed in liver at vit K presence. It is prothrombinase complex main part. Norma: 0,01 g/l. Minimal level - 10-20%. Hemophilia D (Stuart-Prawer’s disease) is developed at its absence or strong reducing of its concentration.
XI. Rozental’s factor, plasma thromboplastin predecessor - glycoprotein, is formed in liver, takes part in prothrombinase formation on internal way. Norma: 0,005 g/l. Hemophilia C (Rozental’s disease) is occurred at its absence or strong reducing of its concentration.
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XII. Hageman’s or contact factor - protein, is activated by negatively charged surface, adrenaline, kallikrein. It triggers prothrombinase and fibrinolysis external and internal ways. Norma: 0,03 g/l. Bleeding doesn’t occur even at its concentration decreasing up to 1 per cent.
XIII. fibrinase, fibrin-stabilizing factor (FSF) – globulin, is synthesized by fibroblasts, megalocaryocytes; it stabilizes fibrin. It is necessary for reparational processes normal course. Norma: 0,01-0,2 g/l. Minimal level: 2-5 per cent.
XIV. Fletcher’s factor, prekallikrein- protein, participates in XII-th factor, plasminogen, high-molecular kininogen activation. Norma: 0,05 g/l. Minimal level - 1%.
XV. Fitzgerald’s-Flozhe factor, high-molecular fibrinogen – is activated by kallikrein, is involved in XI, XII-th and fibrinolytic agents activation. Norma: 0,06 g/l. Minimal level: 1 per cent.
The blood coagulation process may be divided into 3 phases.
SCHEME 2. COAGULATION HEMOSTASIS
The first one includes the complex of consequent reactions leading to the prothrombinase forming. The prothrombinase forming can be realized via two routes: extrinsic (from injured tissue) or intrinsic (from blood).
The extrinsic route of the prothrombinase forming provides the obligatory presence of the thromboplastin (or Factor III, tissue factor). The prothrombinase forming via the extrinsic route begins with the factor VII activation by the interaction with the thromboplastin. In its turn, the factor VII transforms the factor X into the active state. Further the factor Xa activates the factor V. The factors III+IV+ Xa +Va form the complex compound named the prothrombinase. Via the extrinsic route the prothrombinase is synthesized very quickly (it takes the seconds!).
The factor XII (the contact factor) is an important initiator of the intrinsic prothrombinase forming route. The kallikrein and high – molecular kininogen (HMK) are the participants of this reaction. The contact factor is activated by any injured surface, skin, the collagen, the adrenaline and transforms the factor XI in its active state. The XIa influences directly the factor IX, transforming it into the factor IXa. Its specific activity is directed to the factor X protheolysis (converting it into its active form) and occurs on the platelet phospholipid surface at the necessary factor VIII participating. The whole factor complex on the phospholipid platelet surface received its name as the thenase ( the thenase complex). As it was mentioned above, the kallikrein and high – molecular kininogen (HMK) are the participants in a blood coagulation process by means of which the extrinsic and intrinsic routes combination takes place. The intrinsic pathway is more prolonged in time (up to 5-6 minutes) as it is accomplished with a great number of different blood coagulation factors. It is also implemented without vessel wall injuring (e.g. at the adrenaline concentration increasing that activates the factor XII).
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The second phase of blood coagulation is a transition of prothrombin to thrombin which is performed by the prothrombinase. It is a proteolytic prothrombin cleavage resulting in the enzyme thrombin presence. This enzyme possesses the coagulative activity. It takes only several seconds.
The third phase of blood coagulation is a fibrinogen transition to fibrin. At first under the influence of the thrombin two fibrin-peptides A and two fibrin-peptides B are released. As a result of it the fibrin-monomere is formed. Further, the soluble fibrin is formed due to the polimerization process. But because of the XIII factor (fibrinase) activation its transition into the insoluble fibrin (fibrin-polymere) is taking place. Next, this fibrin plug is reinforced thanks to the platelets action (they release the protein thrombosthenin). This process is known as a retraction. The plug in its turn is named a clot. The fibrin net becomes gradually tight. That’s why the clot causes the vessel occlusion and the bleeding is ceased.
One observes II,VII,IX,X,XI,XII and XII factors physiological decreasing in new-borned. On the contrary, V and VIII-th coagulational factors concentration is at adult level in them. In low-weighted, immature new-borned one can see more expressed decreasing of these factors.
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Umbilical cord bandaging terms and first child attaching to mother’s breast time influence greatly on haemostatic indexes. One must hurry up with the first and to perform the second as soon as possible. On the 3rd day of child birth procoagulants level is decreased that leads to hypocoagulation. Further, blood coagulation factors begin their increasing practically till adult level.
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