PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Factor VII”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1977

Combined factor VII and factor VIII deficiency due to a casual association of heterozygosis for factor VII deficiency and hemophilia A.

A patient with combined factor VII and factor VIII deficiency is discussed. The propositus is a 21-year-old male who presented a mild bleeding tendency. The patient appears to be a hemophilia and at the same time heterozygote for factor VII deficiency. This conclusion is based on the fact that heterozygosis for factor VII deficiency was present in the father and in other relatives of the paternal side. On the contrary, no factor VII deficiency was present in the maternal side of the family. However, the maternal grandfather was known to have been a bleeder and the propositus' mother, his sister and his aunt had low-normal factor VIII levels and were probably hemophilia A carriers. This type of combined factor VII and factor VIII deficiency appears to be due to the casual association of two independently segregating defects.

Adult↗
PubMed1975

Activation and control of factor VII by activated factor X and thrombin. Isolation and characterization of a single chain form of factor VII.

Factor VII purified as previously described, was found to consist of two polypeptide chains joined by disulfide bridges. We now report the isolation and 200,000-fold purification of a single chain form of Factor VII. This was accomplished by protecting the molecule against proteolysis by including benzamidine during the entire purification. The purification was essentially as previously reported except that barium cirtate was substituted for barium sulfate as an absorbant for Factor VII as it resulted in a 4-fold increase in yield. Single chain Factor VII is rapidly hydrolyzed by Factor Xa in the presence of calcium ions and phospholipids, and by thrombin, to a two-chain form which possesses at least 85 times the Factor VII clotting activity of the single chain species. The two-chain form of the enzyme requires tissue factor in order to activate Factor X. From the observed rates of activation of Factor VII by Xa in the presence of calcium ions and phospholipids, it was calculated that at approximately physiological concentration, Factor VII activity would increase at an initial rate of 20-fold per min; this reaction is sufficiently rapid to constitute a feedback control mechanism. The action of thrombin is approximately 40-fold slower under these conditions. Diisopropylphosphorofluoridate inactivates the single chain and two-chain forms of Factor VII at approximately equal rates. After inhibition, the single chain species could be cleaved but not activated by proteolysis.

Animals↗
PubMed1990

Increased activity of factor VII and factor VII-phospholipid complex measured using a Normotest system in subjects with hyperlipidemia.

Coagulation factor VII and factor VII-phospholipid complex (factor VIIpl), an activated form of factor VII, were measured using a Normotest system in 128 patients with various types of hyperlipoproteinemias and in 45 control subjects. A positive correlation was found between both factors VII (p less than 0.001) and VIIpl (p less than 0.0001) and serum triglycerides. Similar correlations were established with very low density lipoproteins. A positive correlation was also observed between factor VIIpl and total cholesterol, whereas inverse correlations were found with high-density lipoproteins for both factors VII and VIIpl. No positive correlation could be found between low-density lipoproteins and factors VII and VIIpl. This study has shown that patients with hyperlipoproteinemias associated with high serum triglyceride levels, with or without high cholesterol levels, have increased activity of factors VII and VIIpl, both previously associated with an increased risk of coronary heart disease.

Adult↗
PubMed1975

Isolation and characterization of bovine factor VII.

Factor VII (proconvertin) has been purified approximately 5 x 10(5)-fold from bovine plasma with an overall yield of 30%. The isolation procedure involves barium sulfate adsorption and elution, DEAE-Sephadex batchwise adsorption and elution, benzamidine-agarose column chromatography, heparin-agarose column chromatography, and preparative polyacrylamide gel disc electrophoresis. The final product was homogeneous when examined by gel electrophoresis in the presence of sodium dodecyl sulfate. A minimal molecular weight of 45,500 was determined by sedimentation equilibrium. The molecular weight estimated by sodium dodecyl sulfate gel electrophoresis was 54,000. Factor VII is composed of a single polypeptide chain possessing an amino-terminal sequence of Ala-Asn-Gly-Phe-Leu-. The amino acid and carbohydrate compositions of factor VII are also reported.

Acetylglucosamine↗
PubMed1992

A novel congenital haemostatic defect: combined factor VII and factor XI deficiency.

Isolated deficiencies of factors VII and XI are both rare. Not surprisingly, therefore, combined factor VII and XI deficiency has not been reported previously. We report here a kindred with a combined heterozygous deficiency for both factors VII and XI. The proposita is a 28-year-old woman who had both a prolonged prothrombin time (PT) and a prolonged activated partial prothrombin time (APTT) associated with a mild bleeding tendency. Coagulation studies were performed on the six available members of this kindred. The PT and APTT were normal or mildly abnormal in five of these individuals. Factor VII coagulant activity (VII:C) varied from 0.33 to 0.77 units/ml in affected subjects. In contrast, the concentration of factor VII-related antigen for the six individuals ranged from 0.68 to 2.10 units/ml. Comparable factor VII:C levels were obtained when each subject's plasma was tested with either a rabbit or a human thromboplastin reagent. Factor XI coagulant activity was less than 0.5 units/ml in three of the six subjects and normal (approximately 1.0 units/ml) in the other three. The concentrations of thrombin-antithrombin-III and prothrombin fragment 1.2 were within normal limits for all individuals. In addition to being associated with heterozygous factor XI deficiency, the abnormal factor VII molecule in the plasma of affected individuals in this kindred appears to represent a newly described mutation. This is suggested by the pattern of reactivity with thromboplastin from different species, the normal tissue factor binding and the bleeding tendency in heterozygous individuals in this kindred.

Adult↗
PubMedDate not supplied

Specific assays of hemostasis proteins: factor VII.

Factor VII (FVII) activity should be measured in order to evaluate the risk for coronary artery disease. The measurement of FVII by means of a standardized clotting method seems to be influenced by the thromboplastins used, while the FVII-deficient plasmas do not affect the results.

Blood Coagulation Tests↗
PubMed1976

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.

Animals↗
PubMed1990

The importance of residues 195-206 of human blood clotting factor VII in the interaction of factor VII with tissue factor.

Previous studies indicated that human and bovine factor VII exhibit 71% amino acid sequence identity. In the present study, competition binding experiments revealed that the interaction of human factor VII with cell-surface human tissue factor was not inhibited by 100-fold molar excess of bovine factor VII. This finding indicated that bovine and human factor VII are not structurally homologous in the region(s) where human factor VII interacts with human tissue factor. On this premise, we synthesized three peptides corresponding to regions of human factor VII that exhibited marked structural dissimilarity to bovine factor VII; these regions of dissimilarity included residues 195-206, 263-274, and 314-326. Peptide 195-206 inhibited the interaction of factor VII with cell-surface tissue factor and the activation of factor X by a complex of factor VIIa and tissue factor half-maximally at concentrations of 1-2 mM. A structurally rearranged form of peptide 195-206 containing an aspartimide residue inhibited these reactions half-maximally at concentrations of 250-300 microM. In contrast, neither peptide 263-274 nor peptide 314-326, at 2 mM concentration, significantly affected either factor VIIa interaction with tissue factor or factor VIIa-mediated activation of factor X. Our data provide presumptive evidence that residues 195-206 of human factor VII are involved in the interaction of human factor VII with the extracellular domain of human tissue factor apoprotein.

Amino Acid Sequence↗
PubMed1977

Platelet adhesiveness and aggregation in combined factor V and factor VIII deficiency and in combined factor VII and factor VIII deficiency.

Platelet aggregation and adhesiveness were studied in 3 patients with combined factor V and factor VIII deficiency and in 3 patients with combined factor VII and factor VIII deficiency. The first three patients belonged to three different kindreds whereas the second group belonged to the same kindred. Serotonin C14 uptake and release was also found to be normal in these patients. These studies indicate that platelet function is normal in combined defects of factor VIII. These findings were in agreement with the presence of a normal bleeding time and a normal factor VIII antigen level in all these patients.

Blood Coagulation Disorders↗
PubMed1979

Factor VII Padua 2: another factor VII abnormality with defective ox brain thromboplastin activation and a complex hereditary pattern.

A new factor VII abnormality is presented. The propositus was a 9-yr-old child who presented a mild bleeding tendency characterized by epistaxis and easy bruising. The parents were not consanguineous, but they came from the same area. The laboratory features were mild prolongation of prothrombin time and P.P. test and normal partial thromboplastin and Stypven cephalin clotting times. The Thrombotest was moderately prolonged. Factor VII was 40%-50% of normal using rabbit or human brain thromboplastin, but only 13%-24% using ox brain thromboplastin. Factor VII cross-reacting material (CRM) was about 50% of normal. The father, a paternal aunt, and a paternal cousin showed similar clinical and laboratory findings. The brother of the propositus, the mother, and other members of her family showed about 50% factor VII activity and CRM and were considered to be heterozygotes for true factor VII deficiency. Similar findings were also present in the father and in the brother of the affected cousin. The defect in the propositus seems to consist of a double heterozygosity between abnormal factor VII and heterozygous factor VII true deficiency. The factor VII abnormality appears to consist of abnormal reactivity toward ox brain tissue thromboplastins and appears to be different from previously described factor VII abnormalities. The name factor VII Paudua2 is proposed for this condition.

Adolescent↗
PubMed1992

The role of phospholipids and the factor VII Gla-domain in the interaction of factor VII with tissue factor.

Whether or not the factor VII Gla-domain is involved in the high-affinity interaction of factor VII and tissue factor via calcium-dependent interactions with surrounding phospholipids is unknown. To investigate this, we have purified the factor VII Gla-peptide (FVII-GP) from digested recombinant human factor VIIa and assessed its effect on factor VII:tissue factor interactions. FVII-GP inhibited the activation of factor X by factor VIIa in the presence of either soluble or cell surface tissue factor half-maximally at 0.5 microM and 2.7 microM, respectively. However, FVII-GP failed to inhibit the specific binding of factor VIIa to cell-surface tissue factor, and did not inhibit the ability of tissue factor to stimulate the amidolytic activity of factor VIIa. Unrelipidated tissue factor apoprotein stimulated the amidolytic activity of factor VIIa to the same extent as relipidated tissue factor apoprotein. These findings suggest that the factor VII Gla-domain does not directly interact with tissue factor, but rather is important for calcium binding and concomitant expression of other factor VII epitopes necessary for tissue factor recognition and binding. To test this hypothesis, we have prepared a monoclonal antibody against a putative factor VII epitope that participates in the interaction of factor VII with cell-surface tissue factor (peptide 195-206) and assessed its ability to bind to factor VII in the presence and absence of calcium. Binding of this monoclonal antibody (PW-4) to intact factor VIIa was calcium-dependent and could be inhibited in a dose-dependent manner by peptide 195-206.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1976

The activation of human factor X in sodium citrate: the role of factor VII.

Human factor X was purified by several different procedures yielding products which had varying amounts of factor VII and factor IX. Treatment with CHCl3 during the fractionation of the factor X removed 95% of the factor VII and factor IX activity and the resulting factor X activated more slowly when incubated in 25% sodium citrate. Removal of residual factor VII by DEAE cellulose chromatography yielded a factor X which activated still more slowly and less completely. When the factor VII, removed by chromatography, was added to the chromatographed factor X, the ability to be activated in 25% sodium citrate was restored. Confirmatory evidence for the role of factor VII in this reaction was the inhibition of the conversion of the factor X by both DFP and SBTI.

Citrates↗
PubMed1977

Activation of bovine factor VII by hageman factor fragments.

During the early events of coagulation of human blood by the intrinsic pathway, factor XII is activated to a form which can activate factor XI, and is proteolytically fragmented to smaller species (30,000 daltons and 70,000 daltons) which have lost most of the ability to activate factor XI but which can activate prekallikrein rapidly. The effect of these fragments on factor VII was studied. It was found that these Hageman factor fragments promoted rapid proteolysis of one-chain factor VII to a more active two-chain form. The amino-terminal sequences of the chains of activated factor VII were found to be Ala-Asx-Gly- and Ile-Val-Gly-, the same as were earlier observed after activation of factor VII by activated factor X. This finding indicates that initiation of coagulation by the intrinsic pathway also primes the extrinsic pathway.

Amino Acid Sequence↗
PubMed1977

Activation of bovine factor VII (proconvertin) by factor XIIa (activated Hageman factor).

Bovine factor VII (proconvertin) is a plasma glycoprotein that participates in the extrinsic pathway of blood coagulation. It has a molecular weight of 45 500 and is composed of a single polypeptide chain with an amino-terminal alanine residue. Factor VII is readily converted to factor VIIa by factor XIIa (activated Hageman factor) employing an enzyme to substrate weight ratio of 1:50. Factor VIIa is composed of a light and a heavy chain held together by a disulfide bond(s). The heavy chain, which is formed from the carboxyl-terminal region of the precursor, contains an amino-terminal sequence of Ile-Val-Gly-Gly-. The heavy chain also contains the active-site sequence of -Phe-Cys-Ala-Gly-Tyr-Thr-Asp-Gly-Thr-Lys-Asp-Ala-Cys-Lys-Gly-Asp-Ser-Gly-Gly-Pro-His-. This sequence is homologous with the active-site region of a number of plasma serine proteases. These data indicate that factor VII is a typical precursor of a serine protease which is converted to an enzyme by factor XIIa by the cleavage of a single, internal peptide bond.

Amino Acid Sequence↗
PubMed1990

Synthesis, purification, and characterization of an Arg152----Glu site-directed mutant of recombinant human blood clotting factor VII.

Coagulation factor VII circulates in blood as a single-chain zymogen of a serine protease and is converted to its activated two-chain form, factor VIIa, by cleavage of an internal peptide bond located at Arg152-Ile153. Previous studies using serine protease active-site inhibitors suggest that zymogen factor VII may possess sufficient proteolytic activity to initiate the extrinsic pathway of blood coagulation. In order to assess the putative intrinsic proteolytic activity of single-chain factor VII, we have constructed a site-specific mutant of recombinant human factor VII in which arginine-152 has been replaced with a glutamic acid residue. Mutant factor VII was purified in a single step from culture supernatants of baby hamster kidney cells transfected with a plasmid containing the sequence for Arg152----Glu factor VII using a calcium-dependent, murine anti-factor VII monoclonal antibody column. Purified mutant factor VII was indistinguishable from plasma-derived or recombinant wild-type factor VII by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and migrated as a single band with an apparent molecular weight of 50,000. The average specific activity of several mutant factor VII preparations was 0.00025 unit/micrograms, or 0.01% of that observed for recombinant wild-type factor VII preparations. The clotting activity of mutant factor VII was, however, completely inhibited following incubation with dansyl-Glu-Gly-Arg chloromethyl ketone, suggesting that the apparent clotting activity of mutant factor VII was due to a contaminating serine protease.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Chloromethyl Ketones↗
PubMed1992

Hereditary factor VII deficiency in pregnancy: peripartum treatment with factor VII concentrate.

This report describes pregnant sisters with severe factor VII deficiency and peripartum management with factor VII concentrate. In this family, two affected members had previously developed severe postpartum hemorrhage when managed with fresh frozen plasma. Therapy-related complications owing to plasma infusion included viral disease transmission and pulmonary edema. Therefore, to lessen the risks of complications, specific factor therapy was initiated shortly before parturition in both patients. Factor VII concentrate was administered prior to delivery and every 6 hr for the next 72 hr to keep trough levels at approximately 10%. Based on peak and trough levels, the mean factor VII half-lives were determined to be 3.6 and 5.7 hr. Use of the concentrate was associated with uncomplicated delivery and minimal postpartum bleeding.

Factor VII↗