Acquired antithrombin III deficiency and thrombosis in the nephrotic syndrome.

Antithrombin III levels were studied in relation to the occurrence of thromboembolism in 48 patients with various degrees of proteinuria. Nine of these patients had clinical signs of thrombosis, including four with renal vein thrombosis. In eight of these nine patients, antithrombin III concentrations were below 70 per cent. There was a significant negative correlation between the antithrombin III concentration and the urinary protein excreation (P less than 0.001). Antithrombin III was found in the urine of 32 of 42 patients. There was a significant correlation between the renal clearance and the degree of antithrombin III serum deficiency (P less that 0.001). The clearance and serum level of albumin closely paralleled these changes. We conclude that thrombosis in patients with severe proteinuria is associated with a deficiency of antithrombin III due to urinary excretion of this protein.

The abnormal factor IX of hemophilia B+ variants.

A rather large proportion of the hemophilia B patients can be characterized as hemophilia B+ because of the presence in their plasma of a protein which is immunologically identical with human factor IX. In a group of 33 hemophilia B patients we found 14 cases of hemophilia B+ belonging to 11 independent pedigrees. The variant factor IX molecules of these families have been compared with respect to the following properties: 1) factor IX activity and its dependence on phospholipid concentration; 2) factor IX antigen; 3) prolongation of prothrombin time with an ox brain thromboplastin; 4) electrophoretic mobility; 5) Ca(+) binding capacity; 6) affinity for binding to heparin and 7) susceptibility of the factor IX antigen to contact-induced activation. In the study of these parameters the use of a precipitating antibody against highly purified human factor IX showed to be of great value. According to our criteria at least 7 different factor IX variants were present in the 11 families with hemophilia B+ studied. Because of this rather high heterogeneity a suitable nomenclature for subclassification of hemophilia B+ variants is proposed.

Metabolism of the coagulation factors of the prothrombin complex in hypothyroidism in man.

The metabolic rate of prothrombin, factors VII, IX and X, was studied in nine hypothyroid patients. Disappearance rates of the four vitamin-K-dependent factors, called the prothrombin complex, were measured after assumedly complete blocking of their synthesis with adequate doses of a coumarin congener (acenocoumarol). Reappearance rates were assessed by induction of synthesis with high doses of vitamin K1 (phytomenadion) when stable hypocoagulability had been achieved. Normal values for these rates were derived from earlier studies in our laboratory. In hypothyroid patients the rates of both disappearance and reappearance were significantly slower for all factors tested. Practical consequences of these observations are discussed. The initial level of factor-IX activity in all nine patients was substantially lower than in normal individuals. Therapy by thyroxine-substitution led to normal levels of factor-IX. This implies a divergency in the retardation of the breakdown and production rates in hypothyroidism. The reappearance rate was indeed found to be more retarded than the disappearance rate.

The functional defect of factor VIII Leiden, a genetic variant of coagulation factor VIII.

Factor VIII Leiden is a genetic variant of coagulation factor VIII which has been detected in the plasma of a patient with mild haemophilia A. In this patient's plasma factor VIII procoagulant antigen was in 5-fold excess over factor VIII procoagulant activity, indicating the presence of an abnormal factor VIII molecule. The variant factor VIII was isolated from the patient's plasma, and its functional properties were studied in a factor X-activating system consisting of purified components. The isolated factor VIII Leiden was normally activated by factor Xa and by thrombin, but the activity of the factor VIIIa was about 3% of normal. The defect of factor VIIIa Leiden was studied by comparison with normal factor VIIIa in kinetic experiments of factor Xa formation. The results support the hypothesis that factor VIIIa Leiden has a reduced affinity for phospholipid-bound factor IXa in the intrinsic factor X-activating complex.

Molecular variant of factor VII.

Two patients with severe factor VII deficiency appeared to be different with respect to the presence of inactive factor VII-like material in their plasma. The inactive material, demonstrated in one patient's plasma and adsorbable onto BaSO4, inhibits the thrombotest-system and is capable of neutralizing a heterologous antibody against factor VII in a fluid phase system.

The influence of the thyroid function on the metabolic rate of prothrombin, factor VII, and factor X in the rat.

The influence of the thyroid function on the metabolic rate of prothrombin, factor VII, and X was studied in the rat. Disappearance rates of the three coagulation factors were measured after synthesis had been blocked with appropriate doses of warfarin, and reappearance rates were assessed upon induction of synthesis by high doses of vitamin K1 injected into rats displaying coumarin induced hypocoagulability. No statistically significant difference in the disappearance and production rates of any of the factors could be found between normal euthyroid rats and thyroxin-treated hypothyroid rats proven to be euthyroid. The differences between the two euthyroid groups and the hypothyroid group were highly significant, however: hypothyroidism results in an approximately 50% decrease of the metabolic rates of the three coagulation factors under study. The reappearance of the three factors, under euthyroid as well as hypothyroid conditions, showed a biphasic pattern: in the first two hours after vitamin K1 administration to warfarin treated rats, a rapid reappearance was observed, to the same extent for all three factors, in hypo- as well as euthyroid rats. This finding suggests that in vitamin K1 deficiency an intracellular accumulation of precursor proteins (PIVKAs) occurs, which after rapid conversion into biologically active coagulation factors by vitamin K1 are shed into circulation. The subsequent phase of reappearance is much slower and reflects the synthesis rate of coagulation enzymes. It is characteristic for each factor and clearly slower in hypothyroid rats than in euthyroid rats. From this an influence of thyroid function on the synthesis rate of the protein moiety of coagulation factors can be inferred. An apparent difference between disappearance and reappearance rate of the coagulation factors in the plasma, particularly pronounced for factors VII and X in euthyroid rats, could theoretically be explained as the consequence of the model used for derivation of these rates.

Carrier detection of haemophilia B by using an intragenic restriction-fragment length polymorphism.

We analysed DNA from individuals of five families with haemophilia B, including nineteen potential carriers. A gene-specific probe was used to reveal a TaqI restriction-fragment length polymorphism. Segregation analysis of the polymorphic marker and the deleterious mutation within families allowed diagnosis at the gene level for 16 out of the 19 potential carriers, two proving to be carriers and 14 non-carriers. The obvious advantage is that lyonisation, which is a limiting factor when gene product (clotting factor IX) measurements are used for carrier detection, does not interfere with this procedure and that the result is a definitive diagnosis instead of a risk estimate. The method also permits prenatal diagnosis on chorionic villi in the first trimester of pregnancy. Restriction-fragment length analysis, based upon the probe and restriction enzyme used in this study, will be informative for approximately 45% of the individuals at risk of carrying or transmitting the haemophilia B mutation.

Orthotopic liver transplantation: an experimental study on mechanisms of hemorrhagic diathesis and thrombosis.

The hemorrhagic diathesis after transplantation of preserved livers generally is attributed to intravascular coagulation, whereas postoperative "hypercoagulability" of the blood is considered the main cause of thrombosis of the hepatic artery anastomosis. Since our preliminary studies, however, suggested other mechanisms, parameters of coagulation, fibrinolysis, and platelet function were prospectively studied before and after 28 orthotopic liver transplantations, with and without preservation, in dogs and pigs. In addition, the arterial anastomoses were evaluated routinely by angiography and, after removal at reintervention or autopsy, inspected for thrombosis and tested for fibrinolytic activity and fibrin deposition. Concerning the hemorrhagic diathesis, prolongation of bleeding time without concomitant thrombocytopenia was the main abnormality found and occurred only in the nine dogs with liver transplants previously preserved for 3 to 6 hours. As only two of the nine dogs had postoperative hemorrhage of clinical significance, we consider surgically imperfect hemostasis facilitated by an acquired platelet dysfunction the principal cause of hemorrhage. Thrombosis of the arterial anastomosis was found in 38 percent of animals in which an end-to-end anastomosis was made but was not encountered with celiac artery-aorta anastomoses. Local factors due to surgical technique therefore appear most important in the pathogenesis of thrombosis of the hepatic artery anastomosis, although the postoperative hyperfibrinogenemia and diminished local and systemic fibrinolytic activity may contribute as well.

Immunoradiometric assay of procoagulant factor VIII antigen (VIIICAG).

An immunoradiometric assay of procoagulant factor VIII antigen was developed using a human antibody to the procoagulant activity of factor VIII (VIII:C). The assay measures specifically the antigen related to factor VIII procoagulant activity (VIIICAG) both in plasma and in serum. VIII:C and VIIICAG were measured in a group of healthy individuals and in a group of haemophilia A patients. In haemophilia A at least four groups can be recognised on the basis of the presence or absence of VIII:C and VIIICAG and the VIII:C/VIIICAG ratio.

New method for the rapid detection of vitamin k deficiency.

A new method is introduced for the rapid detection of vitamin K deficiency. The method is based on the direct measurement of the precursor factor II molecules that enter the blood in cases of vitamin K deficiency. The practical use of the new method has been evaluated on the basis of the results obtained in 28 plasma samples of patients suspected of liver disease and/or vitamin K deficiency.

Head injury and coagulation disorders.

Coagulation studies (plasma fibrinogen, ethanol gelation test, and fibrin/fibrinogen degradation product concentration) were done in 150 patients who were admitted after blunt head injury. Results were abnormal in 60 patients and were found to be correlated with the level of consciousness and with the presence of neurological signs. Many of these patients had fractures, but findings in a control group of 26 patients with major fractures without head injury indicate that fractures were not of paramount importance in causing clotting changes. Conclusive evidence of disseminated intravascular coagulation was found in 12 patients. Cases with a fatal clinical course were mostly associated with very high fibrin/fibrinogen degradation product concentrations. Some case histories are reported, confirming the hypothesized correlation between coagulation results and brain tissue destruction rather than brain compression. It was concluded that some degree of disseminated intravascular coagulation in patients with blunt head injury occurs more often than expected and that coagulation studies might have both diagnostic and prognostic value.

Hemostasis and computerized tomography in head injury. Their relationship to clinical features.

Coagulation studies (plasma fibrinogen, ethanol gelation test, and fibrin-fibrinogen degradation product concentration) and computerized tomography (CT) scan examinations were performed in 55 patients with blunt head injury. The frequency of abnormalities in both coagulation study results and CT scans was higher in patients with severe clinical features and clinical course than in less severely injured patients; in these same patients the coagulation results were abnormal (64%) more frequently than the CT scans (40%). Very high fibrin-fibrinogen degradation product (FDP) concentrations were found to be associated with combined hemorrhagic lesions and mass effect on CT scans, but not with a specific localization of brain-tissue damage. It was concluded that: 1) FDP concentration reflects the amount of brain-tissue damage rather than its location, and 2) in the absence of other possible causes of disseminated intravascular coagulation, coagulation studies may be more sensitive than CT scanning in demonstrating brain contusion.

Hemostasis and intracranial surgery.

Preoperative and postoperative coagulation studies were performed in 25 patients undergoing various intracranial surgical procedures. Coagulation abnormalities, mostly consisting of an increase of fibrin/fibrinogen degradation product concentration, either appeared or increased postoperatively in 18 patients. This incidence of postoperative appearance or increase of coagulation abnormalities is higher than that reported in a comparable study of patients after general surgical procedures, and also higher than that of coagulation abnormalities in a previous study of patients after blunt head injury. Although the coagulation abnormalities after intracranial surgery were usually small, they tended to be larger in patients with more extensive intracranial procedures.

Coagulation changes during management of fetal death with 15(s)-15-methylprostaglandin F2 alpha.

Changes in the coagulation mechanism were studied during and after 15(S)-15-methylprostaglandin F2 alpha (15-me-PGF2 alpha) administration for termination of pregnancy because of intrauterine fetal death after 20 wk pregnancy. 12 patients, of whom 2 were under and 6 over 28 wk, were studied. 2-Hourly intramuscular administration of 250 microgram 15-me-PGF2 alpha resulted in expulsion in a median time of 9 h (range: 2-24.3 h). Although the drug may have some inhibitory effect on platelet aggregation, its influence on coagulation and the hemostatic mechanism was negligible.