Experiments on a new clotting factor (factor VII)

A Study of the Effects of the Anti-Rheumatic Drug Ibuprofen (Brufen®) on Patients Being Treated with the Oral Anti-Coagulant Phenprocoumon (Marcoumar®)

The effects of ibuprofen on various parameters relating to blood coagulation were studied in nineteen patients adequately anti-coagulated on a fixed dose of phenprocoumon. The patients were studied for a five-week period and they received a fixed dose of phenprocoumon throughout the whole five weeks. Ibuprofen, 200 mg three times daily was added during weeks three and four.

The following tests were performed at weekly intervals; Prothrombin time (Quick), Factor II, Factor VII, Factor X, Ivy bleeding time and serum concentration of phenprocoumon.

The results showed that in the dosage given, ibuprofen had no significant effect on any of the above tests. It is suggested that the administration of the anti-rheumatic drug, ibuprofen is safe during long-term oral anticoagulation therapy with phenprocoumon.

Newly diagnosed congenital factor VII deficiency and utilization of recombinant activated factor VII (NovoSeven(®))

This case report presents a newly diagnosed congenital factor VII deficiency treated with recombinant activated factor VII (rFVIIa). Congenital factor VII deficiency is a rare autosomal-recessive bleeding disorder that occurs in fewer than 1/500,000 persons. Its presentation can vary from epistaxis to hemarthroses and severe central nervous system bleeding, and correlates poorly with factor VII levels. Our patient had not had a significant hemostatic challenge prior to his presentation and therefore never had any symptomatology suggestive of this disease. He was treated with rFVIIa, and was able to undergo repair of his fractures without bleeding.

Inhibition of tissue factor-activated platelets by low-molecular-weight heparins and glycoprotein IIb/IIIa receptor antagonist

Thrombotic disorders can lead to vascular distress and platelet activation eventually resulting in the rupture of the lesions where a sizable amount of tissue factor (TF) is generated during the pathogenesis of arterial diseases. Since low-molecular-weight heparins (LMWHs) and platelet glycoprotein (GP) IIb/IIIa inhibitors are clinically used for the management of acute coronary syndrome (ACS), studies were taken to determine the effects of these agents on TF-mediated activation of platelets. Freshly drawn native whole blood (WB) from normal healthy volunteers (n = 6) supplemented with a predetermined amount of TF was incubated with equivalent anti-Xa adjusted amounts of various LMWHs at 0.01-1.0 U/ml and tirofiban from 10 to 100 ng/ml. Platelet activation was assessed by measuring the expression of P-selectin (CD62) and the generation of platelet aggregates. At 0.01 U/ml, enoxaparin exhibited a stronger inhibition of TF-induced platelet activation compared to ardeparin and dalteparin. At 0.1 U/ml, these LMWHs produced a comparable inhibition of total P-selectin expression, and at 1.0 U/ml, a marked inhibition was noted. Since enoxaparin produced the best concentration-dependent inhibition of P-selectin expression (saline: 76 +/- 10% vs. 1.0 U/ml enoxaparin: 18 +/- 7%; P < .02) and platelet aggregate formation (saline: 63 +/- 7% vs. 1.0 U/ml enoxaparin: 35 +/- 6%, P < .035), this agent was used for additional studies. Unlike enoxaparin, tirofiban produced a weak concentration-dependent inhibition of platelet activation. At 100 ng/ml, tirofiban produced a 40% inhibition of P-selectin expression and about 60% inhibition of platelet aggregate formation. To elucidate the potential interaction between tirofiban and enoxaparin, the effect of 10 and 100 ng/ml tirofiban was studied with enoxaparin-supplemented WB in a 0.01-1.0 U/ml range. Additive effects between these two agents were noted only at lower concentrations. Thus, at therapeutic concentrations (0.8-1.2 U/ml), enoxaparin itself was capable of inhibiting TF-mediated activation of platelets to > 70%; whereas tirofiban failed to produce such concentration-dependent inhibition. This suggests that the simultaneous administration of GPIIb/IIIa receptor antagonist with LMWH may not have any added benefit in the clinical management of patients with ACS.

Blood clotting factors in cerebrospinal fluid

The activity of blood clotting factors has been investigated in cerebrospinal fluid. No cephalin-like activity was found in cerebrospinal fluid but prothrombin activity averaged about 0.5% of normal plasma activity. The activity of factor VII was negligible in almost all cases. The activity of antihaemophilic factors showed great variation but in the majority of cases it did not exceed 1% of normal plasma activity. High activity for factor V was found in almost all samples of cerebrospinal fluid.

Congenital factor VII deficiency presenting as delayed bleeding following dental extraction. A review of the role of factor VII in coagulation

Recent updated models of the coagulation mechanism suggest that factor VII/thromboplastin complex is the main initiator or trigger of coagulation. Factor VII activation of factor IX is likely to be an important activation pathway. Inhibition of factor VII by tissue factor pathway inhibitor may have a regulatory role in the initiation of coagulation. Defining factor VII's interactions in coagulation physiology may lead to answers for some clinical problems in both hemostasis and thrombosis. We describe a 15-year-old Chinese boy with factor VII deficiency and a factor VII level of 0.08 U/ml. His symptoms were recurrent epistaxis and moderate delayed bleeding post-dental extraction. Such specific symptoms have been reported previously in a study of 40 European patients. It is one diagnosis to consider if a patients main symptom is significant post-dental bleeding. It is possible that there is requirement for higher levels of factor VII at these anatomical sites making them the common sites for symptoms in patients with moderate deficiency. Case reports of rare clotting factor deficiencies will illustrate what may be important in vitro functions of clotting proteins. Therefore reporting should be encouraged, especially during review and reconsideration of models of the coagulation mechanism.

Congenital factor VII deficiency in a patient with an abdominal aortic aneurysm

A patient with congenital factor VII deficiency underwent surgery for an inflammatory abdominal aortic aneurysm. No references in the literature have been found on the management of this coagulation defect in patients who require vascular surgery. We present one such case, with special reference to the perioperative management of factor VII replacement therapy.

Conventional heparin and semisynthetic heparin analogue (SSHA) alteration of blood coagulation after embolic occlusion of human renal circulation

Blood coagulation and fibrinolytic variables were measured in a peripheral vein in a study of 21 consecutive patients before and after angio-embolization of renal carcinoma. The first ten patients received conventional heparin, 5000 IU twice daily, and the following eleven a semi-synthetic heparin analogue (SSHA), 50 mg twice daily, for 5 days. The first injection was given 2 hours before embolization and the last injection at least 12 hours before the last blood sampling. Both groups showed increased levels of FPA on day 5-7, indicating that the anticoagulant influence had ceased. F VII levels decreased only in the SSHA group from embolization to day 3, but were increased in both groups on day 5-7. Levels of thrombin-antithrombin complexes (TAT) were significantly increased in the heparin group 2 hours after embolization, indicating that thrombin activity had been formed. The corresponding TAT level in the SSHA group was not significantly increased. The differences could possibly indicate a different mechanism of action on blood coagulation of SSHA as compared with heparin, with involvement of extrinsic pathway and maybe by-passing antithrombin III inhibition.

Effect of parenteral oestrogen on the coagulation system in patients with prostatic carcinoma

Patients with prostatic carcinoma on oral oestrogen therapy have an altered coagulation system and suffer cardiovascular side effects. Oestrogens--especially oral oestrogens--are potent inducers of liver synthesised proteins, including coagulation factors. We have assessed the effect of non-oral oestrogen on the coagulation system in patients with prostatic carcinoma. Twelve patients were given monthly intramuscular injections of 320 mg polyoestradiol phosphate (PEP). No additional oestrogens were given. No change was found in any of the coagulation factors, including factor VII, with the exception of a significant decrease in antithrombin III. No patient, including 38 patients treated with PEP, had any cardiovascular complications after a mean follow-up period of 12.9 +/- 0.7 months; 76% of the patients responded to treatment. Parenteral administration of oestrogen caused a less marked change in the coagulation system than oral administration and should be the treatment of choice for prostatic carcinoma.

Hemolysis as a Factor in Clinical Chemistry and Hematology of the Dog

Serum biochemical, hemostatic, and hematologic analytes were determined by four laboratories on dog serum or plasmas containing increasing amounts of hemolysate. From the results of testing, interferographs were prepared to aid in decision making and to enhance visualization of the effects of hemolysis on the determination of the analytes. Heniktsus consistently interfered with the analysis of creatinine phosphokinase, lactic dehydrogenase, aspartate aminotransferase, lipase, and albumin, all of which appeared to increase with increasing hemolysis. The results for the remainder of the biochemical, hemostatic, and hematologic analytes varied greatly among analyzers or methods, rarely in a predictable manner, indicating that each laboratory should evaluate the effects of hemolysis on each analyzer and for each method used, in order to make informed decisions on the use of hemolyzed but irreplaceable samples.

Effects of oestrogen therapy and orchidectomy on coagulation and prostanoid synthesis in patients with prostatic cancer

Twenty patients with prostatic carcinoma were randomized to therapy with either oestrogens (n = 10) or orchidectomy (n = 10). Activators and inhibitors of coagulation were studied before treatment, 1.5 months and 6 months after the start of treatment. We found that the patients in the oestrogen group had already increased their factor VII level after 1.5 months (P less than 0.001) and this increased level persisted after 6 months. Factor X tended to increase after 1.5 months and this increase reached significance after 6 months (P less than 0.01). In the orchidectomy groups there was a significant increase in factor X at 6 months (P less than 0.01) and, in addition, antithrombin III (AT III) was increased at this time. Furthermore, there was a parallelism between the increase in factor VII and electrocardiographic evidence of increased coronary insufficiency (r = 0.60; P less than 0.025; n = 15). We found a significant increase of thromboxane as evidenced by the major urinary metabolite 2,3-dinorthromboxane B2 in the oestrogen group as compared to the orchidectomy group. In summary, patients with prostatic cancer during long-term oestrogen treatment were found to have increased levels of factor VII, factor VIII:C and fibrinogen. In addition these patients showed increased formation of thromboxane. The changes imply a hypercoaguable state and platelet activation. No such signs were found after orchidectomy. The findings in the oestrogen group might explain the continuously increased risk of cardiovascular complications during long-term oestrogen therapy.

Modified glycine precipitation technique for the preparation of factor VIII concentrate of high purity and high stability

A modification of the glycine precipitation method for the production of factor VIII concentrate is reported. In this procedure, cryoprecipitate was prepared, washed and dissolved in buffer. Contaminating fibrinogen was precipitated by the addition of 2.8 M glycine buffer at 30 degrees C. The fibrinogen precipitate was removed by filtration using a layer of glass beads. Factor VIII was then precipitated from the filtrate by adding solid NaCl. After centrifugation, the precipitate was resuspended in buffer, desalted, sterilized by filtration, lyophilized and subjected to dry-heat treatment. The procedure gave a good recovery of factor VIII (280 IU/l) and seems applicable to large-scale production. The resulting factor VIII concentrate was especially characterized by its high purity (10 IU/mg) and stability both in the liquid state and during dry-heat treatment.

Rare factor VII variant inherited through genetic variant in proband's mother and another genetic variant in proband's father

An 11-year-old girl with hereditary factor-VII deficiency and her family have been studied for factor VII coagulation activity (VII:C) and factor VII antigen level (VII:Ag). The proband had 11% VII:C, whereas her VII:Ag was at a level that corresponds to about 50% coagulation activity. Forty-two members of the proband's family were tested. This study disclosed that the proband's factor VII deficiency had been inherited through both her mother and her father. Although her father was dead, testing of her father's family showed a factor VII defect of the type VII+ variant, that is, normal production of VII:Ag but reduced VII:C. The maternal side of her family was found to have reduced but identical levels of VII:C and VII:Ag (variant VIIR). The proband's factor VII deficiency is therefore apparently inherited through two different variants, and that could explain this rare genetic type of factor VII deficiency. To our knowledge no such variant has ever been described.

The vitamin K-antagonism of salicylate and warfarin

When administered in high dosages, salicylate acts as a vitamin K-antagonist: it induces a decrease of the plasma concentration of the Gla-containing coagulation factors and an accumulation of microsomal substrates for vitamin K-dependent carboxylase in the liver and in the lung. In vitro the drugs inhibit the DTT-dependent reductases which mediate the reduction of vitamin K epoxide and vitamin K quinone. NADH-dependent reductase and vitamin K-dependent carboxylase are not inhibited.

Clotting factors secreted by monocytes and macrophages: analytical considerations

The secretion of clotting factors by rat spleen macrophages and human peripheral blood monocytes has been studied. The results show that the amount of clotting factors measured depends critically upon the characteristics of the assay system used. The presence of warfarin, salicylic acid or thrombin in the culture medium is shown to decrease the vitamin K dependent clotting factor activity in the supernatant after in vitro culture of rat spleen macrophages and human peripheral blood monocytes.

The binding of Gla-containing proteins to phospholipids

It is demonstrated here that osteocalcin, the Gla-containing protein from bone, is unable to interfere with the binding of the blood coagulation factors to phospholipid vesicles. Therefore, it seems that besides the Gla residues other structural features of the coagulation factors are required for their effective binding to phospholipid surfaces.

Studies on a family with the factor VII defect

Investigations in a family with an isolated factor VII deficiency are reported. In one of the propositi VII Ag was reduced, in all other family members VII Ag was in the low normal range. Other investigators have observed various activation patterns of factor VII in four deficient families which were tested with thromboplastins from different sources. In contrast to most of these earlier studies the degree of activation with different thromboplastins was very similar regardless which thromboplastin was tested. These results confirm the heterogeneity of the factor VII defect. Platelet aggregation which was tested in one of the propositi with ADP, adrenaline, and collagen was found to be normal. No cold activation of factor VII was observed.

A study of hemostasis in ischemic cerebrovascular disease: IV. A five year follow-up of some blood coagulation parameters also including fibrinopeptide A, factor XII and prekallikrein

Twenty-seven young adults (mean age 46) with ischemic cerebrovascular disease (ICD) were reinvestigated about 5 years after discharge and compared to 67 healthy controls. Factor VIII related antigen was again found significantly (p less than 0.005 and p less than 0.001) increased in male as well as female patients and a significant (r = 0.66, p less than 0.001) correlation was found with earlier data. Factor VIII biological activity was again found increased, significantly (p less than 0.001) in males. In contrast to earlier results antithrombin antigen and activity were significantly (p less than 0.001) decreased in males. This finding and decreased levels of factor XII in female patients (p less than 0.001) and of prekallikrein in male patients (p less than 0.01) could reflect disturbed regulatory functions or possibly constitutional differences. As in most subjects no increase of fibrinopeptide A was found, there was no sign of continuous activation of the whole coagulation sequence. Since hemostatic abnormalities were unrelated to acute phase reacting proteins they were obviously of a different nature than unspecific response to tissue damage and acute stress. High levels of factor VIII and low levels of antithrombin imply that the coagulation system could be more easily activated when other factors coincide, e.g. intimal lesions in carotide arteries.

Blood coagulation changes during effective thrombolysis using urokinase and heparin

The efficacy and the safety of a new urokinase dosage regimen (loading dose 250,000 IU, initial maintenance dosage 2,000 IU/kg/h in combination with heparin) was studied in ten cases of deep vein thrombosis with regard to the changes of the blood coagulation and fibrinolytic enzyme system. The coagulation analyses demonstrated a pronounced activation of the fibrinolytic system with a statistically significant (p less than 0.05) shortening of the euglobulin clot lysis time and increase of the FDP. The fibrinogen concentration ranged from 50-100 mg/dl already after 12-36 hours. Plasminogen was reduced by 63%, alpha 2-macroglobulin by 32% and factor VIII:C by 42% (p less than 0.05 each). The decrease of fibrinogen (Clauss method) related well to the method of Ratnoff and Menzie, the reduction of plasminogen and the shortening of the euglobulin clot lysis time. According to our data, a sufficient plasma fibrinogenolytic activity may permit on its own an assessment of an adequate therapy with urokinase and the requirements of dose adjustment. The dosage regimen applied here proved effective and readily controllable. Relevant side reactions were not observed.

Post-translational carboxylation of preprothrombin

In summary, in this review on the function of vitamin K in post-translational modification of precursor proteins by carboxylation of certain glutamyl residues, I have tried to cover in particular the recent work on the reaction, the enzymes involved and the mechanisms being considered. In doing this I have also considered vitamin K, its discovery, its functional form and the possible relation of its metabolism to the carboxylation reaction. Equally the various vitamin K-dependent gla-containing proteins currently known have been described. The carboxylation of synthetic small molecule exogenous substrates and the synthesis and metabolism of the products of carboxylation are of great help in studying the reaction. Structural specificity of vitamin K analogs in vivo and in vitro has been compared and the use of various antagonists in vivo and in vitro considered in attempts to gain an understanding of the overall reaction. The reactions subsequent to carboxylation, e.g., the activation of prothrombin to thrombin via serine proteases and the related activation of the other vitamin K-dependent proteins have not been considered in this review. The review has not covered prothrombin or other vitamin K-dependent protein isolation, nor the determination of these proteins. As the vitamin K-dependent protein carboxylation story has developed over the past six years, a number of reviews have been written which help in keeping up with the various aspects of the field as it has expanded. These reviews refer to many of the papers I have had to eliminate due to space limitations. They are referenced as 469-489. The review is in no sense comprehensive and many papers have been missed or only mentioned. I have tried to concentrate on the more recent work and, thus, much of the very fine work of the 1940's on vitamin K chemistry is hardly mentioned. Some redundancy has been built into the organization of the review so that a reader can obtain a reasonable view of any one section without having to search the whole review for all possible relevant information on any particular part of the field.

Factor VII deficiency

This report describes three patients with factor (F) VII deficiency: two adult siblings and an unrelated 5 1/2-month-old child who succumbed after several central nervous system (CNS) hemorrhages. This event prompted a review of the literature concerning the incidence and characteristics of intracranial hemorrhage in congenital F VII deficiency. Of 138 patients reported to have F VII deficiency, only 75 were considered to have a true deficiency. There was a 1:1 sex distribution with a 19% incidence of consanguinity in the 63 families which these 75 patients represented. CNS hemorrhage occurred in 12 of the 75 proven factor-deficient patients -- an incidence of 16.0%. There was a 1.4:1 female predominance in this group with a 44.4% incidence of consanguinity in their nine families. Except for one patient with hypertension, there was no history of preceding trauma or previous underlying CNS abnormality, though head trauma with a difficult vaginal delivery may have occurred in five infants. Diagnostic lumbar puncture or ventricular tap revealed bloody, xanthochromic cerebrospinal fluid in five. Five patients with F VII deficiency developed a CNS hemorrhage prior to 1 week of age, and none survived. Seven patients older than 1 week of age suffered such an event, and four of these survived. It is concluded that the greatest risk factor for development of CNS hemorrhage is trauma related to the birth process.

Hyperfibrinolysis and hypercholesterolaemia in salt-intoxication in pigs

Non-acute salt-intoxication in pigs leads to hyperfibrinolysis and a continuous rise in cholesterol due to an increase in the LDL fraction. Morphologically, spherical microthrombi, vascular wall infiltration and changes to organs have been found, as have also been described in shock or stress situations.

Influence of age, sex and blood groups on 15 blood coagulation laboratory variables in a reference material composed of 80 blood donors

15 blood coagulation and fibrinolysis variables were determined in 80 healthy blood donors. Males were shown to have significantly higher levels of factor VII and factor X, and in subjects with blood group O significantly lower levels of VIIIR:AG were observed. In individuals with blood group O a skewed distribution of VIIIR:AG suggested a mixed population of this antigenic determinant. No significant correlation (r less than 0.36) was found between age and any of the laboratory variables.

Disseminated intravascular coagulation in association with congenital neuroblastoma

A 3-month-old infant with neuroblastoma complicated by progressive depletion of coagulation factors and a microangiopathic haemolytic anaemia is described. Specific anti-tumour therapy corrected the haemorrhagic defect on 2 occasions, but did not affect tumour bulk significantly, although a fall in urinary vanillyl-mandelic acid was seen. The rarity of this association and the possible underlying mechanisms are discussed.

Synthesis of procoagulant factor VIII, factor VIII related antigen and other coagulation factors by the isolated perfused rat liver

The synthesis of factor VIII and other coagulation factors has been studied using an isolated, perfused rat liver. Synthetic function of the liver was validated by adding [35S]L-methionine to the perfusion medium and performing two-dimensional crossed immunoelectrophoresis and autoradiography on samples obtained during perfusion. Progressive incorporation of radioactivity into plasma proteins was demonstrated. This was inhibited by cycloheximide. Coagulation factor assays demonstrated synthesis of factors II, IX and X and of factor V and procoagulant factor VIII (VIIIC). Synthesis of factor VIII related antigen (VIIIRAg), measured in an immunoradiometric assay, was not significantly demonstrated. Addition of warfarin to the perfusion medium inhibited the synthesis of factors II, IX and X but not of factors V and VIII. Cycloheximide completely inhibited synthesis of all coagulation factors but actinomycin acted only after a latent period. Reticuloendothelial cell blockade was attempted by adding ethionine to the perfusion medium or by administration of Indian ink to the donor animals prior to removal of the livers. In these instances synthesis of factor V and factor VIIIC was inhibited but not that of factors II, IX and X. The results confirmed the functional capacity of the isolated liver for synthesizing proteins and the vitamin K dependent coagulation factors, and suggested similar kinetic features for the synthesis of factors V and VIIIC. Failure to detect significant VIIIRAg synthesis in these experiments is consistent with the hypothesis that this protein is released by vascular endothelial cells throughout the body and is activated or joined to VIIIC or stimulates its production in the liver.

Congenital factor VII deficiency. A report of four new cases

Four new cases with congenital homozygous factor VII deficiency are described. Factor VII levels were reduced to less than 1%, 3%, 8% and 10%, respectively. The incidence and severity of bleeding symptoms were well correlated with the measured factor VII activity. In the severe case of factor VII deficiency (less than 1%) a home treatment program was started because of severe recurrent hemarthroses. This entailed transfusions of 20 U/kg body weight prothrombin complex or factor VII concentrate in case of acute bleeding approximately every three weeks. These transfusions have been carried out successfully without any problems. In contradiction, two brothers with hypoproconvertinemia (factor VII 8% and 10% respectively) reached an age of more than 70 years. Despite replacement therapy postoperative bleeding followed one appendectomy, whereas no postoperative bleeding followed patients requiring Achilles tendon lengthening and an above knee amputation and only slight bleeding followed a tonsillectomy. Based on our experience we suggest that in patients with factor VII deficiency of less than 10%, when undergoing surgery, should be maintained a minimal factor VII activity of 10--15% during the first three postoperative days.