Accelerate Blood Coagulation Research Articles

Roles of sialic acid in the function of bovine factor V

Bovine factor V was treated with highly purified neuraminidase to yield asialo factor V. Different preparations of factor V were found to exhibit heterogeneity with respect to the content of sialic acid, which ranged from 5% to 12%. The activity of asialo factor V in accelerating blood coagulation was found to be significantly greater than native factor V; thus, sialic acid is not essential for activity but may modulate its function. Asialo-factor V was 3.8 times more stable as calculated from the thermal decay constant at 37 °C. when compared to unmodified factor V. The increase in activity of factor V by thrombin was biphasic after removal of all sialic acid residues. The binding of asialo-factor V to phosphatidyl ethanolamine, as, characterized both by kinetics and by sucrose density gradient ultracentrifugation, resulted in an inactive complex. Double immunodiffusion shows that the sialic acid component of factor V is not necessary for its antigenicity.

BLOOD COAGULATION INITIATION BY A COMPLEMENT-MEDIATED PATHWAY

A variety of complement-activating substances, including inulin, immunoglobulin aggregates, bacterial endotoxins, and staphylococcal protein A, were found to initiate blood coagulation through a complement-mediated pathway. These substances markedly accelerated blood coagulation in normal rabbit blood. That this clot-promoting activity requires an intact complement system was demonstrated by an almost total lack of effect on blood from rabbits with an inherited deficiency of the sixth component of complement (C6). Small amounts of isolated C6 conferred to C6-deficient blood the ability to respond with accelerated coagulation upon activation of the complement system. In addition, it was determined that activation of complement through the previously described C3 activator system resulted in the initiation of blood coagulation. The participation of C1, C2, and C4 was not necessary.

Blood-Clotting Enzymology

Abstract During the past quarter century perhaps no single phenomenon has attracted so much attention in biology and medicine as blood clotting. It plays a role in numerous clinical conditions where it was not taken into account previously. Knowledge of the basic mechanisms recently passed through a tumulous stage of growth, but is now delineated in terms of simple enzymology. Most of the components have been obtained in purified form. There are three main events: the formation of autoprothrombin C (F-Xa, thrombokinase), the formation of thrombin, and the formation of fibrin. Prothrombin itself is a more marvelous protein than was predicted. It is a protein aggregate that contains the precursor of thrombin, the precursor of autoprothrombin C, as well as accessory protein. When blood coagulation is initiated by tissue injury, large amounts of autoprothrombin C activity arise in the presence of calcium ions and tissue thromboplastin. When there is no tissue injury, small amounts of autoprothrombin C are produced by platelet cofactor I (F-VIII, AHF) which functions with the lipids of platelets. Autoprothrombin C is the enzyme which produces thrombin activity, and being a part of the prothrombin aggregate it is in close proximity to the specific bond(s) that must be split to get thrombin activity. Although autoprothrombin C alone is sufficient to produce thrombin, the reaction is greatly accelerated by plasma Ac-globulin (F-V), lipids from platelets, and calcium ions. The acceleration produced by components functioning in pairs and relays makes possible the essential integration with the anatomic location of resources. Tissue materials pair with plasma resources to produce autoprothrombin C, and then they pair with another plasma component (Ac-globulin) to make autoprothrombin C function. In the absence of tissue injury, platelet materials pair with plasma resources to produce autoprothrombin C, and then platelets again work with another plasma component (Ac-globulin) to support the function of autoprothrombin C. Platelets are essential because their lipids are needed for the formation of autoprothrombin C, as well as for accelerating its function. Whatever involves platelets can be the stimulus to accelerate blood clotting; this includes Hageman factor. Platelets are the true point of beginning for the first step in blood clotting and are involved in the second and third. Vitamin K deficiency, or counteraction of Vitamin K by Dicumarol reduces prothrombin synthesis by the liver. As a consequence the precursor of thrombin, the precursor of autoprothrombin C, and the accessory protein of the molecular aggregate which constitutes prothrombin is reduced in concentration. It has been found possible to produce abnormal conditinos experimentally and have relatively more of the precursor of thrombin released to the blood than is normally associated with the precursor of autoprothrombin C. Up to the point of incorporation to form a single prothrombin molecule, the synthesis of subunits proceeds by separately operating mechanisms.

Adrenaline and experimental thrombosis.

The acceleration of blood coagulation in vivo by adrenaline was first demonstrated by Vosburgh and Richards in 1903. They showed in man that adrenaline in doses of 7 μg. per kg. body weight shortened the coagulation time by about 50 per cent. Subsequent studies led to conflicting conclusions until the experiments of Cannon and Gray in 1914, who showed that small doses of adrenaline promoted coagulation, but that larger doses inhibited it. This was confirmed by later investigators (Waldron, 1951; Forwell and Ingram, 1957) but, so far as we know, the effect in normal animals of adrenaline on thrombus formation, as distinct from coagulation, has not been explored. More recently, evidence has been presented that adrenaline increases Factor‐VIII activity (Ingram, 1961), shortens platelet survival and increases platelet turnover (Adelson, Rheingold, Parker, Buenaventura and Crosby, 1961; Özge and Mustard, 1964). Recently, Mitchell and Sharp (1964) and O'Brien (1963) have shown that adrenaline promotes platelet aggregation in vitro.In the present study we have directed our attention to the effect of this drug on blood coagulation, platelets and thrombus formation. Quantitative study of thrombus formation has been made possible by the development of a standard extracorporeal circulation which allows precise measurement (Downie, Murphy, Rowsell and Mustard, 1963). In view of the findings of earlier investigators studying coagulation, it seemed important to determine how dosage levels affect the results.

Arterioselerosis with Reference to Blood Coagulation

It is now generally accepted that lipemia has a close relationship to the pathogenesis of arteriosclerosis, and blood coagulation has been reported to be accelerated by alimentary lipemia. But the precise mechanism of this atherogenic factor of lipemia is not yet clarified. In thromboembolic patients and alimentary lipemia hypercoagulability has been reported to be observed frequently. Thus recently the atherogenic factor of lipemia has been discussed with reference to this hypercoagulability induced by lipemia. In this paper the author reported the effect of alimentary lipemia on blood coagulation factors and the effect of experimentally accelerated blood coagulation on the occurrences of atherosclerosis.

The Clot-Promoting Effect of Adenosine-5’- Diphosphate (ADP). I. Mechanisms of Action

Summary1. ADP accelerates blood coagulation by at least two mechanisms. One is by causing release of coagulant phospholipids from platelets. The other is by activation of a plasma coagulation factor whose action is early in thromboplastin generation.2. Possible mechanisms of ADP’s effect on blood coagulation are discussed.3. These findings suggest that ADP may play a more significant role in the mechanisms of hemostasis and in the pathophysiology of thrombosis than has heretofore been supposed.

Changes in the blood coagulation system in rabbits rats, and dogs in sudden death

In dogs and rabbits death from asphyxia was accompanied by accelerated blood coagulation, increased tolerance of the plasma to heparin and intensified fibrinolytic activity of the blood. Twenty five minutes later these changes were enhanced and fibrinogen concentration dropped. With the death of dogs from asphyxia and trauma, thrombi were revealed in 60 min; in the first case these thrombi were subjected to a greater destruction within the 24 h. Postmortem examination of rats in 60 min demonstrated the presence of thrombi in the heart. No thrombi were present 24 h later in rats which died of asphyxia, whereas in those which died of a trauma the thrombi were retained. With the death occurring as a result of asphyxia more favorable conditions are created for thrombolysis than after death from trauma.

Clotting power and protein composition of lymph and blood after acute blood loss

In experiments on dogs a study was made of the role played by the lymphatic system in the acceleration of blood coagulation after acute blood loss. After blood letting the clotting time decreased in all the experiments except one. As distinct from blood, the rate of lymph coagulation remained unchanged. Disturbed lymph circulation, caused by cannulzation of the chief lymph collectors, did not exclude acceleration of blood coagulation after blood letting. Thus, acceleration of blood coagulation following blood loss was not caused by the penetration of factors stimulating hemocoagulation through the lymph. The factor, causing blood hypercoagulation, does not gain access to the lymph in significant quantity.

Participation of the reticular formation of the pons in the regulation of blood clotting

In unanesthetized rabbits with electrodes implanted into the cerebral cortex and into the reticular formation of pons varolii a study was made of the effect produced by the stimulation of the reticular formation of pons varolii on the electric activity of these portions of the brain, blood coagulation time and of the factor V, prothrombin and heparin content in the blood. Following stimulation of the rostral and caudal portions of the reticular formation of pons varolii-blood coagulation was accelerated, prothrombin level increased, whereas factor V and heparin concentrations dropped. With the same stimulation of the medial, portion of the pons Varolii reticular formation there sets in, at first, a transitory acceleration of blood coagulation which is then followed by its deceleration and the reduction of factor V and prothrombin blood content. The EEG “activation reaction” is mostly accompanied by acceleration of blood coagulation, whereas an increase of the slow oscillations amplitude and the acceleration of “spindle” bursts—by its deceleration. The EEG normalizes earlier than the initial blood coagulation time does.

On the mechanism for accelerating blood coagulation in dogs associated with intravenous injection of adrenalin

In experiments staged on 16 dogs an inquiry was made into the effects of intravenous adrenaline injections (0.15 mg/kg) on the functional state of the blood coagulative system. Venous blood procured prior to and 5, 30, and 60 minutes after adrenaline injection was tested. Under the effect of adrenaline blood coagulation time (in vitro) and silicon blood coagulation time are halved, whereas the plasma heparin tolerance almost doubles. Prothrombin blood activity and fibrinogen concentration show no statistically authentic change. Blood antithrombin activity diminishes almost by 50%. Blood fibrinolytic activity shows a considerable rise.

On the significance of the fibrinolytic system of the blood

Subject to a study in experiments on dogs (involving intravenous administration of nicotinic acid and thromboplastin, blood loss) and in observations of patients (operative interventions, atherosclerosis, thromboembolic disease, etc.) were interrelationships between the blood coagulation, fibrinogen concentration, fibrinolytic and fibrinogenolytic activity. The blood of healthy individuals and dogs showed fibrinolytic activity to be present regularly. Fibrinogenolytic activity, on the other hand, was absent. In stress conditions (surgical intervention, blood loss, nicotinic acid administration) the blood coagulation was accelerated with blood fibrinolytic activity increasing at the same time (no fibrinogenolysis was present). Intensified fibrinolytic activity of the blood is a normal protective body reaction, occurring with acceleration of blood coagulation. This regularity is disturbed in pathological conditions. Association of accelerated blood coagulation with diminished fibrinolysis (atherosclerosis, thromboembolic disease) creates favorable conditions for thrombosis. There is no direct relationship between blood fibrinogen concentration and its fibrinolytic activity. This is explained by the fact that, as a rule, activation of fibrinolytic system in the body leads to the intensification of its fibrinolytic properties, but not of fibrinogenolytic ones.

The effect of chlorpromazine on the coagulation of the blood and the arterial pressure

There are many scientific papers disapproving the well-known statement of Connon that emotions stimulate blood coagulation. Not excitation, but intensification of the inhibitory process in the cerebral cortex is accompanied by stimulation of the blood coagulation process. It is also known from literature (I. A. Akopov) that general hemostatic and sedative properties in medicinal substances are regularly conjoint. A combination of hypotensive properties with the acceleration of blood coagulation was also noted (gendon, reserpine, redergam etc.—Kochetkova).

Thromboplastin generation by saliva

In order to determine directly whether saliva has any specific thromboplastic activity or whether its effect in accelerating blood coagulation is nonspecific, we compared saliva with commercial tissue thromboplastins in the following modified hematologic tests: 1. 1. In the one-stage prothrombin-time test, the prothrombin activity curve was simulated very closely when saliva replacing tissue thromboplastin was used in the same manner. 2. 2. In the thromboplastin-generation test, saliva showed a definite thromboplastin generation over a period of time, constantly increasing and then deteriorating. Commercial tissue thromboplastin did not show any detectable generation at any time or at any concentration.

Antigen-induced histamine release from blood cells and acceleration of blood coagulation: Inhibition by tame

Antigen-induced histamine release from blood cells and acceleration of blood coagulation: Inhibition by tame

Effect of acetoacetate on blood coagulation in rabbits and its prevention

The effect of Na-acetoacetate injections on blood coagulation factors was studied. No change in blood coagulation factors occurred in 4 weeks, but continued treatment of acetoacetate for 8 weeks was found to cause hastening of blood coagulation. The hydrolyzed product of glucose cycloacetoacetate was found to prevent the acceleration of blood coagulation in acetoacetate-treated animals.

The "retarded" thromboplastin-generation test. Its use in the study of accelerated blood coagulation.

The "retarded" thromboplastin-generation test. Its use in the study of accelerated blood coagulation.

The problem of the thromboplastin activity of the blood

The mechanism of increased thromboplastin activity of the blood was studied on 100 patients operated on in connection with fibromyoma of the uterus and in 25 experiments with acute blood loss in dogs. The thromboplastin activity increased during the postoperative period by one and a half times, antithromboplastin activity by two and a half times. These changes occurred as soon as 2.5 hours after the operation, being most pronounced on the third day. The number of blood platelets increased insignificantly and only on the eighth postoperative day. Acute blood loss is associated with increased thromboplastin activity, reduction of antithromboplastin activity and a drop of the platelet count. The rise of the blood thromboplastin activity after the operations and blood losses are associated with reduced blood antithromboplastin activity. Increased blood thromboplastin activity, leading to accelerated blood coagulation, should be regarded as one of the manifestaions of “stress” reaction.

THE EFFECT OF COLLOIDAL SILICA ON BLOOD COAGULATION

SUMMARYColloidal silica accelerates blood coagulation by adsorption and partial denaturation of a specific plasma protein, the Hageman factor. Quantitative measurements show that the activity of the silica depends on the particle diameter. It is suggested that geometrical relations between the silica and the protein molecules account for these differences in activity. The implications of certain anomalies of this reaction are considered.

The role of interoceptors in the regulation of blood coagulation

The role of interoceptors of carotid sinus and of the arch of aorta in acceleration of blood coagulation in acute blood loss was investigated. It was revealed by 29 experiments on rabbits and 10 on dogs that local anemia of sinocarotid zones causes reflex acceleration of blood coagulation. Blood loss in rabbits with denervated carotid sinuses is associated with the weaker response of acceleration of blood coagulation, than in normal animals. With exclusion of the sinus, depressor and vagus nerves the acceleration of the blood coagulation and increase of thrombin titer is not as considerable as following blood loss in the intact animals.

Studies on the physiology of the follicular fluid.

The formation of the follicular fluid is a phenomenon which is intimately connected with the normal function of the ovary. In spite of this, the physiology of the follicular fluid is very poorly understood at present. It therefore seemed desirable to investigate this question. In the following the author gives a summary of his published and unpublished work in this field. There are a number of earlier investigations on the follicular fluid. With regard to the composition of the liquor, it has been claimed that it contains 10–40 per cent of dry substance, mainly proteins and so-called pseudomucin (Oertel, 1924). Cholesterol (Parhon, 1925) and oestrogenic hormone (MacCorquodale, Thayer & Doisy, 1936) are also present. It has further been suggested (Dahlberg & Ăkesson, 1930) that the follicular fluid contains a substance which depresses the maturation of other follicles. Both inhibition and acceleration of blood coagulation have been ascribed to