In Vitro Effects of the Acylated StreptokinasePlasminogen Activator Complex BRL 33 575 Incubated with Normal Human Plasma

Thrombolysis with acylated streptokinase-plasminogen complexes is aimed to achieve fibrinolysis without systemic fibrinogenolysis. The p-aminobenzoyl-streptokinase-(Lys)-plasminogen-complex (BRL 33 575) should be particularly useful due to its slow deacylation rate. Unexpectedly, repeated doses of 10 mg of BRL 33 575 (corresponding to 310'000 streptokinase equivalent units) induced systemic effects in patients though less than streptokinase alone. In vitro incubation of normal human plasma with BRL 33 575 at concentrations used in patients resulted in nearly complete consumption of α2-antiplasmin and plasminogen and significant fibrinogenolysis within 3 hr. This demonstrates that - despite of slow deacylation of BRL 33 575 - the small amounts of activator generated are highly efficacious in activating plasma plasminogen under conditions in which no physiological clearance of the free activator takes place. Simulating the calculated activator release from BRL 33 575 by infusing equivalent amounts of streptokinase into plasma resulted in less pronounced effects. This is probably explained by anti-streptokinase antibodies which will neutralize the initially infused streptokinase but will be bound by BRL 33 575.

Our in vitro experiments indicate that further clinical studies should be done with lower doses of BRL 33 575 or prolonged dosage intervals.

Inhibition of Fibrinolysis and Fibrinogenolysis in Man: Comparison of ε-Aminocaproic Acid and Kallikrein Inhibitor

Inhibitor of kallikrein and trypsin (KI) extracted from bovine parotis was compared with ε-aminocaproic acid (EACA): both substances inhibit fibrinolysis induced with streptokinase. EACA is a strong inhibitor of fibrinolysis in concentrations higher than 0, 1 mg per ml plasma. The same amount and higher concentrations are not able to inhibit completely the proteolytic-side reactions of fibrinolysis (fibrinogenolysis, diminution of factor V, rise of fibrin-polymerization-inhibitors). KI inhibits well proteolysis of plasma components in concentrations higher than 2,5 units per ml plasma. Much higher amounts of KI are needed to inhibit fibrinolysis as demonstrated by our in vivo and in vitro tests.

Combination of the two substances for clinical use is suggested. Therapeutic possibilities are discussed.

The Measurement of Haemostatic Factors in 16 European Laboratories: Quality Assessment for the Multicentre ECAT Angina Pectoris Study

As part of a European multicentre prospective study involving the measurement of a number of haemostatic factors, a quality assessment (QA) scheme was organized. This paper describes the preparation, design and results of the first Qa exercise, involving 16 European laboratories and 10 haemostatic assays. The design allowed the investigation, for each assay, of the variability between duplicates and the variability between days within each centre, and of the agreement between centres. A graphical presentation of each centre’s performance in comparison to that of others was adopted, which preserved the confidentiality of each centre’s results. The factor VIII clotting activity assay (VIII: C) and the rocket immuno-electrophoresis assays of von Willebrand factor related antigen (vWF R:Ag), antithrombin III, protein C and histidine-rich glycoprotein showed the highest betweenduplicate and between-day coefficients of variation (CVs), whereas the clotting assays of activated partial thromboplastin time and fibrinogen had the lowest CVs. CVs for the enzymatic assays using synthetic substrates of antithrombin III, plasminogen and alpha-2-antiplasmin were between these extremes. The between-centre CVs were high for both the VIII:C and vWFR:Ag assays. The QA exercise showed that, in multicentre studies involving the measurement of haemostatic factors, it is feasible to undertake analysis locally at each centre.

Kombinierter AHG- und PTA-Mangel

Es wird über die Kombination eines Faktor-VIII- und Faktor-XI-Mangels bei einem Patienten mit schwerer Blutungsneigung berichtet. Die Schwierigkeiten der Differentialdiagnose werden aufgezeigt und ähnliche Fälle in der Literatur diskutiert.

Fifteen Coagulation and Fibrinolysis Parameters in Diabetes Mellitus and in Patients with Vasculopathy

Fifteen haemostasis parameters have been measured in 48 normal persons, 36 diabetics without and 44 with complications and 27 with peripheral arterial disease. Since the patients groups are older than normals, part of the differences are due to age. However, the differences are significant between normals and patients. They become highly significant for the diabetics with complications and nephropathy (Table 7). In diabetics without complications factor VIII functions, fibrinogen and thrombin time are related to age whereas there is a negative correlation for the fibrinolytic activity and antithrombin III. The diabetic complications shade off the correlations, which subsist only for VIIIR: CoF, VIIIR: Ag, ATIII and lysis before stasis. With Hbalc as dependent variable VIIIR:CoF is the only significant predictor variable in diabetics (Table 9).

Heparin Cofactor II Determination - Levels in Normals and Patients with Hereditary Antithrombin III Deficiency and Disseminated Intravascular Coagulation

A technique is described to completely remove antithrombin III (AT) from small amounts of human plasma by immunoaffinity chromatography on antibodies against human AT linked to Sepharose 4B. The level of heparin cofactor II (HCII) was not affected by the immunoadsorption. HCII activity was then determined by measuring the rate of human thrombin inhibition by 3 ways: a) activation with heparin in AT-free plasma, b) activation with dermatan sulfate in normal plasma and c) activation with dermatan sulfate in AT-free plasma. The normal range of HCII varied between 0.7-1.5 U/ml, as compared to a normal plasma pool containing by definition 1 U/ml. Highly significant correlations between assays as obtained from 40 normal plasmas proved the suitability of the 3 assays, although the progressive thrombin inhibition by AT, when not removed, contributed about one fifth to the thrombin inhibition by HCII in the presence of dermatan sulfate. There were also highly significant correlations between HCII activity and antigen, as determined by rocket immunoelectrophoresis using specific antibodies against HCII.

Levels of HCII and AT were examined in 7 patients with hereditary AT deficiency and 7 patients with disseminated intravascular coagulation (DIC). In hereditary AT deficiency, whereas the AT activity was reduced by half, levels of HCII activity and antigen were in the normal range. In DIC, a parallel decrease of HCII and AT suggests that HCII may participate in the inhibition of thrombin released during DIC and thus provides an inhibitor reserve, once the AT level becomes subnormally low.

The Contact Phase of Blood Coagulation in Diabetes Mellitus and in Patients with Vasculopathy

The contact phase has been studied in diabetics and patients with macroangiopathy. Factor XII and high molecular weight kininogen (HMWK) are normal. C1-inhibitor and also α2-macroglobulin are significantly elevated in diabetics with complications, for α1-macroglobulin especially in patients with nephropathy, 137.5% ± 36.0 (p <0.001). C1-inhibitor is also increased in vasculopathy without diabetes 113.2 ± 22.1 (p <0.01).

Prekallikrein (PK) is increased in all patients’ groups (Table 2) as compared to normals. PK is particularly high (134% ± 32) in 5 diabetics without macroangiopathy but with sensomotor neuropathy. This difference is remarkable because of the older age of diabetics and the negative correlation of PK with age in normals.

Platelet Aggregation, β-Thromboglobulin and Platelet Factor 4 in Diabetes Mellitus and in Patients with Vasculopathy

We have studied 155 subjects, 48 normals, 36 diabetics without complications, 44 with complications and 27 patients with macroangiopathy. β-Thromboglobulin (β-TG) and platelet factor 4 (PF4) are elevated in the patients groups. There is no correlation between the plasma levels of β-TG and the stages of either retinopathy or macroangiopathy or nephropathy. The difference is more marked between normals and diabetics with neuropathy (p = 0.026). The aggregation response to ADP and platelet activating factor (PAF) is enhanced at lower stimulator concentration. Using the β-TG, PF4 and aggregation values the discriminant analysis allows a distinction of several subgroups especially with nephropathy and neuropathy (Table 6).

Fibrinogen, Factor VIII Related Antigen, Antithrombin III and α2-Antiplasmin in Peripheral Arterial Disease

In 306 subjects, 217 without and 89 with peripheral arterial disease (PAD), VIIIR:Ag and α2-antiplasmin are significantly higher in PAD (p < 0.01). In the PAD negative group the ratio α2-antiplasmin/antithrombin III activity is significantly higher 1.11 ± 0.3 in the patients with an abnormal exercise ECG typical of coronary disease than in normal subjects 1.02 ± 0.2 (p < 0.05). In the PAD positive group antithrombin III concentration is higher in patients with a normal exercise ECG than in patients with abnormal exercise ECG (p < 0.05). The same is true for α2- antiplasmin but not for the antithrombin III activity. Fibrinogen and VIIIR:Ag are higher in patients with a previous myocardial infarction, however, the age is also significantly different as compared to the group without previous myocardial infarction. Disturbance of the cerebral arterial circulation is characterized by an elevation of VIIIR:Ag and of α2-antiplasmin as comapred to the values obtained in patients without this complication. There is a general tendency towards higher α2-antiplasmin values with the extension of the arterial disease.

Heparin Cofactor II: Purification and Antibody Production

Heparin cofactor II (HCII) was purified from plasma to homogeneity. The procedure includes adsorption with (Al)OH3, fractionation with polyethylene glycol 6000, chromatography on QAE-Sephadex A-50, on heparin-Sepharose 4B and on Sephadex G-150. QAE-Sephadex A-50 chromatography provides a good separation of HCII from antithrombin III (AT) and most contaminants having a heparin affinity similar to that of HCII. HCII is eluted at 0.28 M NaCl from the heparin-Sepharose column. After gel filtration on G-150, contaminating AT was removed by immunoadsorption. Purified HCII shows an apparent Mr of 66,500 dal tons as analyzed on SDS-polyacrylamide gel and 62,100 daltons by ultracentrifugation. Antibodies to HCII were raised in rabbits. Former antisera mostly directed to a contaminating protein were used to remove it from the HCII preparation. Antibodies to HCII were made monospecific by immunoadsorption on HCII-free plasma linked to Sepharose 4B. Since many functional AT assays have neglected the presence of HCII in plasma, antibodies to HCII using as immunoadsorbent will provide a more specific test for AT.

Plasmin Inhibitors and Fibrinogen Breakdown During the Initial Phase of Thrombolytic Treatment - The Problem of the α2-Antiplasmin Determination

During the first 3 hr of thrombolytic treatment with porcine plasmin (p-PL) or streptokinase (SK) a rapid decrease of clottable fibrinogen with generation of large amounts of fibrin(-ogen) degradation products (FDP) are found. α2-antiplasmin (α2AP) is rapidly neutralized. Whereas in patients treated with SK more than half of the original plasminogen was consumed, its level remained unchanged during p-PL infusion. When α2AP reaches values below some 20%, spontaneous amidolytic activity towards S-2251 representing either PL-α2-macroglobulin- or SK-plasminogen-complex activity appears. This activity has to be considered in the α2AP assay in order to avoid underestimation of this inhibitor.

Controlled Multicenter Pilot Study of Urokinase – Heparin and Streptokinase in Deep Vein Thrombosis

Thirty-three patients with acute iliofemoral thrombosis were randomly assigned to three treatment groups in a pilot doseranging study of thrombolytic therapy in deep vein thrombosis. One group received tissue culture urokinase in a dose of 2,200 I.U./kg/hr, and a second group in a dose of 1,100 I.U./kg/hr following a loading dose of 4,400 I.U./kg given in ten min. Urokinase was administered for 12 hr periods, alternating with 12 hr periods of heparin. A third group received an initial dose of 250,0001.U. of streptokinase in 20 min, followed by 100,000 I.U./hr. Treatment of all patients continued for three days. At the end of this period little improvement, evaluated by “blinded” interpretation of pre- and post-treatment phlebograms, was found in five out of ten of the higher-dose urokinase patients, seven out of eleven of lower-dosage urokinase patients, and six out of ten of streptokinase patients. Optional treatment for another three days showed little further improvement of urokinase-patients and moderate further improvement in the streptokinase-patients. – Neither of the 2 dosage schemes at intermittent application of urokinase appeared to be advantageous. Urokinase treated patients experienced fewer adverse reactions.

Dissociation of Factor VIII Procoagulant Antigen VIII : CAg and Factor VIII Related Antigen VIIIR : Ag by EDTA - Influence of Divalent Cation on the Binding of VIII: CAg and VIIIR :Ag

Assuming 1 U/ml in titrated plasma, the VIII: CAg concentration was found 1.66 U/ml in EDTA-plasma, 1.09 U/ml in heparinized plasma and 0.67 U/ml in serum. Addition of 10 mmol/1 EDTA to titrated and heparinized plasmas increased VIII: CAg 1.5fold. There was no increase of VIII: CAg in serum. Gel filtration of plasmas on different anticoagulants showed an elution of VIII: CAg in the void volume Vo and in the later fractions. The VIII: CAg amount detected in the internal volume increased following the series heparin < citrate < EDTA. Serum VIII: CAg was eluted at 2.2 Vo. Presence of EDTA in the elution buffer or incubation of plasma with EDTA prior to chromatography caused a displacement of practically all VIII: CAg amount in the internal volume with a peak at 2.2-2.3 Vo. VIIIR: Ag was exclusively detected in the void volume.

Removal of divalent cation by chelation likely exposes more antigenic determinants of VIII: CAg, which are otherwise masked by steric hindrance due to VIIIR: Ag in citrated and heparinized milieu. Moreover gel filtration of plasma in the presence of EDTA completely dissociates VIII: CAg from VIIIR :Ag. The VIII: CAg fragment, having an estimated molecular weight of 70,000, might also be present in serum.

Monitoring of Oral Anticoagulation by an Amidolytic Factor X Assay

The validity of the amidolytic Factor X assay for the control of long term oral anticoagulation (OA) was investigated in 42 patients randomized into 2 groups; PT group (anticoagulant dosage according to PT) and F. X group (anticoagulant dosage based on F. X). An independent expert's dosage according to F. X served for analysis in the former group. In the F. X group the F. X based dosage was considered valid only when not differing by more than 15% from the expert's PT based dosage.

Confirming the good correlation between PT and F. X the study further demonstrates that the changes from one control to the next one, ΔPT and ΔF. X, too, are significantly correlated (r = 0.58, p & 0.001, n = 217). In over one third of the periods the dosage proposals based on PT and F. X were identical and differed by more than 15% in only 12/217 instances.

Our results justify a large trial on the control of OA by the amidolytic F. X assay.

Side Effects of Thrombolytic Treatment with Porcine Plasmin and Low Dose Streptokinase

In the sequential thrombolytic therapy with porcine plasmin and low dose streptokinase side effects are mainly due to bleeding, intolerance reactions are less important. Treatment had to be prematurely stopped in 42 (37%) of 114 DVT cases because of severe bleeding and in 12 (10%) due to intolerance reactions. The corresponding figures for the 45 cases with arterial occlusions are 15 (33%) and 2 (4%) respectively. The intensity of systemic proteolysis as represented by the thromboplastin time is significantly correlated with haemorrhagic manifestations. Macrohaematuria and bleeding from puncture sites are the most frequent haemorrhagic complications followed by spontaneous bleeding into skin and muscles. Non-fatal intracranial bleeding occurred in 1 DVT case (0.9%) and in 2 patients with arterial occlusions (4.4%). The benefit of this potent thrombolytic regimen would greatly improve if a strong reduction of premature treatment stop could be achieved.

Sequential Treatment of Deep Leg Vein Thrombosis with Porcine Plasmin and Low Dose Streptokinase

Sequential treatment of deep leg vein thrombosis with porcine plasmin and low dose streptokinase (10,000-20,000 U/h) produces strong systemic fibrinolysis as demonstrated by the sustained decrease of euglobulin lysis time, of thromboplastin time values in percent, fibrinogen and factor V levels. There is a statistically significant negative correlation between thrombolytic results and euglobulin lysis time. Treatment periods below 3 days are unlikely to give satisfactory results. Occluded vein segments with an apparent median age of 4 days including thrombi older than 10 days (20% of cases) are cleared with an average chance of 50%. Complete dissolution of all thrombi proximal to the crural veins has been demonstrated in 47/114 = 41.2%, some thrombolytic effect in 31/114 = 27.2% and treatment failure in 36/114 = 31.6%. The data favour laboratory monitoring of thrombolytic therapy.

Different Assessment of Plasmin with Different Substrates

The alteration of human and porcine plasmin and the influence of EACA and AMCHA on their activity were investigated. Solutions of both plasmins undergo storage induced alteration, which is best recorded by Chromozym PL, whereas the other chromogenic substrates, S-2251 and S-2302, and casein are less sensitive, and the fibrin plate inadequate. Plasmin amidolytic and fibrinolytic activity is maximally enhanced at 7.6 × 10–3 M EACA and 6.4 × 10–4 M AMCHA, and decay through storage is reversed. The caseinolytic activity seems slightly inhibited at the same EACA and AMCHA concentrations.

Our results show:

1. The quotient: plasmin activity towards Chromozym PL/Activity towards S-2251 is a useful indicator of "plasmin quality". The quotient decreases markedly upon storage of plasmin solutions.

2. Plasmin stability is improved in the presence of AMCHA.

3. It is valueless to add EACA or AMCHA to inhibit plasmin in amidolytic assays since the chosen concentration enhances the amidolytic activity of already formed plasmin.

Purification and Partial Characterization of a Hereditary Abnormal Antithrombin III Fraction of a Patient with Recurrent Thrombophlebitis

A relatively low heparin cofactor activity (0.60 U/ml) was observed in a patient with recurrent superficial thrombophlebitis of the left leg. However, the antigen concentration was in the normal range (1.04 U/ml) and the progressive antithrombin activity was normal. The crossed immunoelectrophoresis in presence of heparin in agarose gel separated the patient's AT-III antigen in 2 fractions with different mobilities. The patient's AT-III was purified for further characterization. The last step of the purification procedure, a heparin-agarose chromatography, led to a separation and a purification of 2 AT-III fractions with different heparin affinities: an abnormal AT-III with reduced heparin affinity and a normal AT-III with a heparin affinity similar to that of AT-III isolated from normal plasmas. Abnormal and normal AT-III share several identical properties as molecular weight, ability to form complexes with thrombin and progressive antithrombin activity.

Sequential Treatment of Arterial Occlusions with Porcine Plasmin and Low Dose Streptokinase

Sequential treatment of arterial occlusions of the leg with porcine plasmin and low dose streptokinase results in a strong systemic proteolysis as already seen in deep leg vein thrombosis. In 31 of 45 patients the blood flow through major arterial segments could be restored. Thrombolytic success is possible within the first two treatment days but for the majority of the cases fibrinolytic therapy for 3-6 days is needed. On the average treatment was 1 day shorter than in DVT cases. No statistical relationship between local thrombolysis and systemic proteolysis was detected.

The thrombolytic efficacy of this regimen compares favourably with earlier experience on fibrinolytic therapy in arterial occlusions.

Reactivity of a Hereditary Abnormal Antithrombin III Fraction in the Inhibition of Thrombin and Factor Xa

Two different AT-III fractions were purified from the plasma of a patient with recurrent superficial thrombophlebitis. The abnormal AT-III fraction (A-AT) was compared to the normal AT-III fraction (N-AT) in the inhibition of thrombin and factor Xa. Without heparin, both inactivate proteases in a similar manner and at the same rate. However, at low heparin concentration the thrombin inhibition proceeds more slowly with A-AT than with N-AT. At high heparin concentration the difference between A-AT and N-AT becomes very small. The inhibition of factor Xa follows a similar pattern. It is suggested that the heparin binding site of A-AT differs from that of N-AT resulting in a decreased heparin cofactor activity.

The Formation of Intermediate Product I in a Purified System The Role of Factor IX or of its Precursor and of a Hageman Factor-PTA Fraction

1. The role of two clot promoting fractions isolated from either plasma or serum is studied in a purified system for the generation of intermediate product I in which the serum is replaced by factor X and the investigated fractions.

2. Optimal generation of intermediate product I is possible in the purified system utilizing fractions devoid of factor IX one-stage activity. Prothrombin and thrombin are not necessary in this system.

3. The fraction containing factor IX or its precursor, no measurable activity by the one-stage assay method, controls the yield of intermediate product I. No similar fraction can be isolated from haemophilia B plasma or serum.

4. The Hageman factor — PTA fraction shortens the lag phase of intermediate product I formation and has no influence on the yield. This fraction can also be prepared from haemophilia B plasma or serum.

The Determination of Antithrombin III

At III levels were measured with six methods in 36 people: 10 healthy controls, 10 women taking a progestagen Lynestrenol and 16 women taking a combined oestrogen-progestagen contraceptive pill.

The reproducibility and the sensitivity of these methods as well as the correlation between methods were studied.

The Hensen and Loeliger technique had a poor reproducibility and the results obtained with the Howie technique were not in good correlation with those obtained with the other methods, especially in the group taking oral contraceptives. The two amidolytic methods using chromogenic substrates were found to be very accurate for antithrombin III activity determination. The rocket Immunoelectrophoresis was more accurate and more practical than the radial immunodiffusion.

With all methods - except the one of Howie–the 10 women taking progestagen Lynestrenol and the 16 taking combined oestrogen-progestagen had a low AT III and differed significantly from the 10 normals tested. No difference was observed between women taking progestagen only or an oestrogen-progestagen combination.

Purification of Factor IX or its Precursor Isolation of a Hageman-PTA Fraction

A purification method is described which allows the isolation of two active fractions: Hageman factor — PTA fraction and factor IX or IX precursor fraction. These two fractions are characterized and some of their properties are indicated.

Quantitative Estimation of Coagulation Factors in Liver Disease. The Diagnostic and Prognostic Value of Factor XIII, Factor V and Plasminogen

20 coagulation parameters were investigated in 144 patients with different liver diseases. The groups of acute hepatitis, chronic active hepatitis and liver cirrhosis were compared and the prognostic value of the coagulation analyses investigated. It is clear that the determination of the factor V activity is a good and easy test for detection of actual liver function. Repeated controls over several weeks revealed with a statistical significance (p <0.0005) that all patients with a factor XIII below 35& and a plasminogen below 19& will die in liver coma, if they have not died beforehand from acute gastrointestinal haemorrhage, acute infection or cardiac arrest.

Plasminogen is also lower in the group of non-survivors but the values of the two groups are overlapping and of no prognostic help in a single case. The possible causes of the diminution of factor XIII activity are discussed.

The Influence of Fibrin Stabilizing Factor on the Growth of Fibroblats in vitro and Wound Healing

Congenital deficiency of Fibrin Stabilizing Factor (FSF) is the cause of both pathological haemostasis and poor wound healing. Experiments with fibroblast cultures were carried out to characterize the latter. Growth of the cultures in the patient’s plasma was quantitatively and qualitatively inferior as compared with the growth in normal control plasma, which contained FSF. Only by addition of normal plasma and purified FSF the poor cell growth was corrected. The necessity of fibrin present in the first stage of wound healing and possible modes of action of FSF in haemostasis and wound healing are discussed.

The Influence of Contact and Prothrombin on Intermediate Product I Formation

In the in vitro generation of intermediate product I, in which non-purified components are used, both prothrombin and foreign surface “contact” are essential for the formation of optimum activity. Most of the time interval required before optimum intermediate product I activity is reached is the time needed for potentiation of intermediate product I as well as for the conversion of prothrombin to thrombin. In the system studied, it is felt that, in the absence of prothrombin, intermediate product I activity is blocked by the presence of an inhibitor. The action of thrombin would then be to overcome the inhibitor. The apparent increase in factor IX activity, observed during the generation of intermediate product I as measured by the one-stage method, is due to the non-specific clot-promoting effect of intermediate product I on the assay.

The Relation between a Naturally Occuring Inhibitor and Prothrombin in Intermediate Product I Formation

1. A method for the separation from clotting factors and the concentration of an inhibitor of intermediate product I present in adsorbed plasma and adsorbed serum is described.

2. This inhibitor is not only stable but also activated at 37° C. At 4° C it loses activity.

3. The inhibitory effect on the formation of intermediate product I is counteracted by small amounts of prothrombin or thrombin.

4. After addition of inhibitor prothrombin is necessary for the formation of intermediate product I in the purified system.

5. The discrepancy, in regard to the need for prothrombin (or thrombin) between the purified and the non-purified system can be explained by the relative amounts of inhibitor in the two systems.

Rabbit Antibodies Against the Procoagulant Activity (VIII:C) of Human Factor VIII

The procoagulant activity VIII:C was separated from factor VIII antigen (VIIIR:Ag) by gel filtration in the presence of 0.25 mol/l calcium chloride. Antibodies (anti-VIII:C) were obtained by immunization of rabbits with VIII:C. The last step of the purification procedure of antibodies consists of an adsorption on VIIIR:Ag-Sepharose 2 BCL as immunoadsorbent to remove contaminating traces of antibodies against VIIIR:Ag. The anti- VIII:C titer remains unchanged during this adsorption (29 Bethesda units per mg). In solution, anti-VIII:C neutralies factor VIII activity (in plasma, cryoprecipitate or in purified form) and the fragment VIII:C without reacting with VIIIR:Ag. Once immobilized on a solid matrix, i.e.2% agarose, it loses over 95% of its inhibitory capacity. The immobilized anti-VIIIR:Ag binds stoichiometrically the antigen and the activity of plasma factor VIII. These results together suggest that factor VIII is composed of 2 different entities, but undissociated under physiological conditions. Immunophysical analyses as a function of pH and temperature of anti-VIII:C and its complex with factor VIII show properties similar to those of homologous antibodies. The antigen determinants of VIII:C (VIII:CAg) are destroyed at low pHs or high temperatures, and VIII:C can no more form a complex with anti-VIII:C. Purified anti-VIII:C is also used in a two-stage assay to detect VIII:CAg or cross-reacting material in some severe haemophiliacs.

The Activation of Plasma Factor XIII with the Snake Venom Enzymes Ancrod and Batroxobin Marajoensis

The snake venom enzymes Ancrod and Batroxobin marajoensis are able to activate human plasma factor XIII as shown by the formation of the γ-dimers. The concentration of γ-dimers increases with the concentration of the activating enzymes. Factor XIII activated by Ancrod or Batroxobin marajoensis is, however, unable to catalyse the incorporation of the amine dansylcadaverine into casein. The partially activated factor XIII is therefore not demonstrable by means of the artificial test system. This factor XIII loses little activity and remains activable by thrombin.

Local Treatment of Recent Arterial Thromboembolic Occlusions with Brinase

Brinase was administered intra-arterially in 16 patients with thrombotic or embolic arterial occlusions. Angiography could be performed before and after treatment in 13 patients. Thrombolysis was obtained in 3 of 9 patients with thrombotic and in 3 of 4 patients with embolic occlusions. In 3 patients severe local side effects occurred.

Assay of Brinase Inhibitors with Soluble and Insoluble Substrates

Two methods for the assay of brinase inhibitors are compared. Neither provided a reliable means of brinase dose prediction. Overdosage can, however, be avoided by preinfusion inhibitor assay.

The Impact of Sequential Quality Assessment Exercises on Laboratory Performance: The Multicentre ECAT Angina Pectoris

As an adjunct to a European multicentre prospective study, five quality assessment (QA) exercises, spanning a period of 2.5 years, were undertaken. In these, fifteen laboratories from eight countries each performed ten haemostatic factor assays. The design of the QA exercises allowed the between-dupli cate, between-day and between-laboratory coefficients of variation (CVs) to be calculated. The between-duplicate CV decreased by a factor of one quarter, and the between-day CV by a factor of one third, over the five exercises. The activated-partial thromboplastin time (APTT) assay consistently showed the lowest CVs, while there was notable improvement in the between-day CVs for von Willebrand factor related antigen (vWF R: Ag) and factor VIII clotting activity (VIII:C), However, the between-laboratory CV assessing extent of agreement between the different laboratories, did not apparently improve over the five exercises. Thus, while QA exercises may be very useful in improving the performance of haemostatic assays according to criteria which an individual laboratory can assess, improving agreement on haemostatic assay results between laboratories may be more difficult to achieve.

Impaired Fibrinolysis as an Essential Contribution to Thrombosis in Patients with Lupus Anticoagulant

Lupus anticoagulants (LA) are IgG or IgM antibodies against phospholipids which in vivo represent an important thrombophilic factor despite their in vitro anticoagulant activity. We investigated the fibrinolytic system of 20 patients with connective tissue disease and positive LA, compared to a control group of 24 age- and disease-matched patients without LA. There was no statistically significant difference of alpha2-antiplasmin, plasminogen, fibrinogen, t-PA activity, D-dimers and heparin cofactor II, between the two groups. Although t-PA was uniformly low in both groups, plasminogen activator inhibitor activity (PAI) was significantly higher in LA cases (p <0.001). Increased PAI levels represent an inhibitory factor of the fibrinolytic defense mechanism, which together with other functional deviations may contribute to the thrombophilic tendency of LA patients.

Coagulation Factors of the Newborn and His Mother

In 50 mothers and their newborns 13 parameters of blood coagulation and fibrinolysis have been investigated. No correlation was found between the activity in the mother’s blood and in the cord blood.

The activity of the factors V, VIII and IX can be so low in the blood of the normal newborn that it is not possible to detect a hereditary coagulopathy early at birth time. Fibrinogen and factor XIII make an exception. The factor XIII is normal in the cord blood, even higher than in the mother’s blood.

The values of fibrinogen measured with different methods disagree (Table 1). These results are discussed in connection with the antithrombin II, antithrombin III, split products and plasminogen values.

Action of Coagulation Factors on Experimental Thrombogenesis and Their Changes after Thrombosis

The action of ellagic acid, serum and acetylsalicylic acid on the frequency of thrombosis has been studied in a modification of the thrombosis model of Blake et al. (1959). Thrombi were formed in the external jugular veins of the rats by irritation with a formalin-methanol solution. The rate of thrombosis is highest with ellagic acid and lowest with acetylsalicylic acid. None of the groups of treated rats differed significantly from the control group. A short activation of coagulation with either ellagic acid or serum does not greatly enhance the thrombosis rate. The action of acetylsalicylic acid in the prophylaxis of thrombosis is not very convincing. Species differences may play a role.

Exhaustive coagulation studies before and after operation showed in each group a specific behaviour of the coagulation factors. There were significant differences between thrombosis positive and thrombosis negative animals. With ellagic acid, however, there was no difference between animals with and without thrombosis.

Factor XII, Plasma Prekallikrein, α2-Macroglobulin and C1-Inhibitor Levels in Renal Allograft Recipients During Immunosuppression with Cyclosporin A – Sequential Measurements over Four Months in 17 Patients

Factor XII clotting activity (F XII), plasma prekallikrein amidolytic activity (PK), α2-Macroglobulin (α2-M) and C1-Inhibitor (C1-Inh) antigens have been measured in 17 patients immediately before and sequentially for up to four months after kidney transplantation. Before transplantation mean F XII and PK levels were normal (99 ± 27% and 102 ± 21%, respectively, mean ± S. D.) and α2-M and C1-Inh levels were slightly elevated (115 ± 55% and 129 ± 32%, respectively, mean ± S. D.). In the first two weeks after transplantation a significant decrease of F XII to 65 ± 27%, of PK to 67 ± 20% and of α2-M to 88 ± 42%, and a rise of C1-Inh to 201 ± 44% (mean ± S. D.) were observed (2 p <0.005). F XII levels four month after operation remained significantly (2 p <0.05) lower than preoperatively. PK and α2-M values, however, were significantly higher (2 p <0.05) at four months as compared to the pretransplant period. Mean F XII levels in the 17 patients at various time points after transplantation correlated positively with PK, α2-M and serum albumin and negatively with CyA level and dose and serum bilirubin. PK and α2-M correlated positively with each other and albumin and negatively with creatinine, bilirubin and CyA (2 p <0.01). Whether CyA has a direct influence on production or consumption of F XII, PK, α2-M and C1-Inh, or whether the changes merely reflect altered protein metabolism awaits further study.

Major Surgery in a Subject with Factor V Deficiency

A further case of parahaemophilia is reported. One year after the correct diagnosis had been made the patient had to undergo cholecystectomy which was performed under prophylactic substitutive treatment with fresh plasma at a factor V level of 31 %. A minimal factor V level of 11 to 12% was maintained throughout the first week after operation. There was no abnormal postoperative bleeding. The half disappearance time of factor V was found to be about 12 h. Infusion of equivalent amounts of fresh plasma supplied a higher yield of factor V in the patient’s plasma before operation than postoperatively what may be explained by an increased diffusion of factor V into the intercellular space resulting from a postoperatively increased capillar permeability. The results are compared with those of other authors.

Quantitative Determination of Platelet Factor 3 Activity

A method for the quantitative determination of platelet factor 3 (PF 3) is described. It is based on the prothrombin consumption and allows the determination of the total PF 3, of the PF 3 made available under various conditions and of PF 3 like activity.

The material to be tested is recalcified in the presence of a normal PPP pool to maintain the intrinsic clotting factors in the optimal concentration range. After an appropriate incubation the coagulation is stopped by a citrate solution and the clot removed. The residual prothrombin activity in citrated serum is indirectly proportional to the PF 3 activity. This activity can be expressed in per cents by means of a reference curve which can be established with Cephaloplastin (Dade) dilutions. The 100% value is given by the total average PF 3 activity when the platelet count in PRP is adjusted to 100,000 platelets/mm3. An appropriate correction is needed when the prothrombin concentration is too low in the tested PRP.

In 50 healthy blood donors the PF 3 activity ranged between 70-130% with quite small day to day variations.

Properties of 3-(1-Phenyl-Propyl)-4-Oxycoumarin (Marcoumar®) in the Plasma when Tested in Normal Cases and under the Influence of Drugs

A fluorimetric method served to determine Marcoumar in blood plasma. The biological half-time of Marcoumar after an administration of 2.2 mg/10 kg is 6½ days. Variations in maintenance dose requirements seem not to be primarly determined by differences in absorption or excretion of the anticoagulant drug. In therapeutical concentrations about 99% of the drug are bound to plasma protein. Marcoumar can be displaced in vitro from plasma protein by different drugs. The anticoagulant effect is not increased in every case in which the anticoagulant is displaced in plasma from its protein binding.

Quantitative Determination of Plasminogen

A modification of the caseinolytic assay for plasminogen is described. This assay system is characterized by the following features :

1. Urokinase is used as activator achieving a complete activation of the plasminogen whereas with streptokinase caseinolytically inactive plasminogen-activator complexes are formed.

2. All incubation times are reduced to the minimum which is still compatible with accuracy.

3. Results are expressed in percent of a standard of ten normal plasmas.

4. In this two-stage assay-system (activation of plasminogen to plasmin, digestion of casein by plasmin) both stages proceed simultaneously in the same system, thus the plasmin formed is stabilized “in statu nascendi” by the casein.

5. Several conditions (stability of plasminogen in frozen plasma, use of anticoagulants, reproducibility) are defined.

The Formation of the Extrinsic Prothrombin Activator

The formation of the extrinsic activator of prothrombin conversion is investigated. We use the term “extrinsic activator” to avoid ambiguity which could arise when employing the name tissue thromboplastin.

The experiments are carried out with purified clotting factors and congenital factor VII and X-deficient sera. Two steps can be distinguished. First, tissue factor and factor X react together as substrates in presence of Ca ions to form the extrinsic reaction product. The reaction is catalyzed enzymatically by factor VII. In the second stage, the reaction product and factor V (substrate) form the extrinsic activator which in turn can convert the prothrombin to thrombin.

A Hitherto Undescribed Congenital Haemorrhagic Diathesis Probably Due to Fibrin Stabilizing Factor Deficiency

A new congenital haemorrhagic diathesis is described. It is characterized by the poor and slaw wound healing, profuse and long bleeding and by probable absence of spontaneous and joint bleeding. It is due to the deficiency of a factor which makes the fibrin clots insoluble in urea. This factor is probably the fibrin stabilizing factor of Laki and Lorand, although no proof of their identity can yet be given. The deficiency appears in both sexes and is probably an autosomal recessive disease.

Intoxication with Phenprocoumon (Marcoumar) Pharmacokinetics and Side Effects

A case of severe Marcoumar intoxication is described. Eleven hours after the intake a plasma concentration of 15.75 µg/ml was found which corresponds approximately to the 5-fold therapeutic concentration. Repeated administration of vitamin K1 made it possible to avoid extreme lowering of the activity of the clotting factors II, VII and X and to prevent bleeding. Side effects were not observed. The biologic half-life of Phenprocoumon has been found to be shortened at high plasma concentration (3.7 instead of 5.9 days). It is probable that in extreme concentration the drug is less strongly bound to the plasma proteins.

Some Aspects of Kinetics of the First Stages of Blood Thromboplastin Formation

The first stages of blood thromboplastin generation were investigated. Plasma Thromboplastin Antecedent, Prephase Accelerator, and Hageman factor are involved in the reactions taking place during the lag period. This phase is followed by the formation of intermediate product I. Studying the kinetics of this particular reaction it was possible to attribute to factors VIII and IX the rôle of substrates and to Stuart-Prower factor the rôle of an enzyme. It appears that in haemophilia B serum two distinct factors are lacking, the genuine factor IX, and the prephase accelerator (PPA). An hypothesis explaining tentatively the activation of a precursor to PPA and genuine factor IX is offered.

Differentiation of the Factor VII Complex

A factor recently described and for which the designation Stuart-Prower Factor is proposed, was investigated. It is detected by the usual Factor VII assay but differs from this factor (Matching experiments with plasma and serum of Owren’s Factor VII deficient patient). Stuart-Prower factor is necessary for the conversion prothrombin-thrombin with tissue thromboplastin as well as for the formation of blood thromboplastin. Therefore lack of Stuart-Prower factor produces abnormal Quick’s prothrombin time (not normalized with Russell’s viper venom [Stypven]), and also abnormal prothrombin consumption, abnormal recalcification time and abnormal thromboplastin generation with serum. Matching experiments with plasma and serum of the patients of Graham and Hougie, Telfer Denson and Wright, and Beaumont and Bernard show that we are dealing with the same defect. Physiological and physico-chemical properties are indicated. The possible relationship between Stuart-Prower factor and Factor X is discussed. A critical review with 59 cases of the so-called Factor VII deficiency is given. Investigation of the family of our patient Delia B. indicates that the mode of inheritance is an intermediate autosomal one.

Über einen neuartigen kongenitalen Gerinnungsdefekt (Mangel an Stuart-Faktor)

Bei einem Säugling mit ungewöhnlich schwerer hämorrhagischer Diathese wurde ein Gerinnungsdefekt festgestellt, der folgende Charakteristika aufweist: Quicksche Prothrombinzeit stark verlängert, Gerinnungszeit mit Russel Vipers Venom stark verlängert, Prothrombin-Verbrauchstest pathologisch, Faktor-VII-Bestimmung mit bovinem Seitzplasma (einstufig) 1 bis 3%. Faktor IX (einstufig) 30%, Thromboplastingeneration mit Patientenserum stark pathologisch, wird durch Mischung mit Hämophilie-B-Serum völlig, mit Marcoumarserum (Beginn der Marcoumartherapie) ebenfalls normalisiert. Plasma und Serum des Patienten „Stuart” (Graham) und unseres Patienten zeigten in allen Tests dasselbe Verhalten.