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PubMed1987

Accelerating effect of zinc ions on the surface-mediated activation of factor XII and prekallikrein.

The effect of zinc ions on the surface-mediated activation of factor XII and prekallikrein was studied, using the contact system reconstituted with the purified proteins from bovine and human plasmas. The sulfatide-mediated activation of factor XII and prekallikrein in the presence of high-molecular-weight (HMW) kininogen was remarkably accelerated by 10(-5) M zinc ions. This accelerating effect was observed only in the presence of HMW kininogen. The kinetic analysis of the accelerating effect of zinc ions demonstrated that zinc ions reduce the Km values and increase the Vmax values on the activation of factor XII by kallikrein and on the activation of prekallikrein by factor XIIa. The value of Vmax/Km increased 26.4-fold in the former reaction and 2.8-fold in the latter reaction, indicating that zinc ions accelerate mainly the activation of factor XII by kallikrein. In the presence of 5 x 10(-4) M zinc ions, typical difference spectra due to a red shift of tryptophan and/or tyrosine residues were observed for HMW kininogen and its derivatives but not low-molecular-weight (LMW) kininogen. Since the concentration of zinc ions required to induce the difference spectra is comparable with that to enhance the activation of factor XII and prekallikrein, it appears that there is some correlation between the conformational change of HMW kininogen and the enhancement of the activation.

Animals↗
PubMed1997

The surface-dependent autoactivation mechanism of factor XII.

The dependency of concentrations of Zn2+ and the negatively charged surfaces, phosphatidylinositol phosphate (PtdInsP), sulfatide and dextran sulfate, on the autoactivation of human factor XII, has been studied. While the autoactivation induced by sulfatide, and low concentrations of dextran sulfate, was unaffected by the presence of Zn2+, that induced by PtdInsP and higher concentrations of dextran sulfate was completely dependent on Zn2+: the excess of Zn2+ needed to induce maximal activity with PtdInsP was 12-fold the concentration of factor XII, while with dextran sulfate it was 40-fold. Determination of the Zn2+-binding properties of factor XII revealed that a total of four zinc ions could bind to each factor XII molecule. The first bound zinc ions (Kd 0.1 microM) induced an increase in the intrinsic tryptophan fluorescence of factor XII, while further titration up to a 40-fold surplus resulted in a quenching of the fluorescence. Binding of the zinc ions that caused the quenching had an average Kd of approximately 1 microM, independent of whether it was determined from the fluorescence changes or by equilibrium filtration. Low concentrations of both sulfatide and PtdInsP induced a fluorescence increase similar to that at low concentrations of Zn2+ but, in contrast to sulfatide, higher concentrations of PtdInsP did not induce a quenching in fluorescence. As the Zn2+-independent activating surface (sulfatide) induced quenching in the fluorescence intensity, while the Zn2+-dependent activating surface (PtdInsP) did not, the quenching, whether it was caused by sulfatide or zinc ions, was assigned to a change in the conformation which resulted in a molecular structure of factor XII that could be autoactivated. Association of factor XII in this conformation on the activating surface was suggested to be responsible for the autoactivation.

Dextran Sulfate↗
PubMed1976

Inhibition of activated factor XII by antithrombin-heparin cofactor.

The activation of Factor XII occurs via fragmentation of this zymogen into a diverse spectrum of enzymatically potent molecular species. To study the interaction of antithrombin-heparin cofactor and heparin with activated Factor XII, we have employed two forms of this enzyme with widely differing physical characteristics and biologic potencies. Antithrombin-heparin cofactor was found to be a progressive, time-dependent inhibitor of both forms. The addition of heparin dramatically accelerated the rates of these interactions. Furthermore, sodium dodecyl sulfate gel electrophoresis of reduced proteins has indicated that antithrombin-heparin cofactor functions by forming an undissociable complex with either species of the enzyme. This complex represents a 1:1 stoichiometric combination of activated Factor XII and inhibitor. In the presence of heparin, both species undergo virtually instantaneous complex formation with antithrombin-heparin cofactor without exhibiting alterations in dissociability or stoichiometry.

Alpha-Globulins↗
PubMed1993

[Recurrent venous thromboses in hypoplasia of the vena cava inferior and factor XII deficiency].

The cause of recurrent pelvic and leg venous thromboses in a 24-year-old man was found to be a combination of two rare anomalies, hypoplasia of the hepatic, prerenal segment of the inferior vena cava and factor XII deficiency (factor XII activity 38%, its antigen 39% of normal), the latter considered a risk factor for thromboembolism. Subsequent fibrinolysis was not successful. No thromboembolic phenomena occurred during the following 16 months of oral anticoagulation with phenprocoumon. When this treatment was discontinued at the patient's behest, there was a recurrence on the contralateral side. Anticoagulation was resumed and has continued now for 1 1/2 years without recurrence. The patient has been largely free of symptoms. Permanent anticoagulation thus seems unavoidable in this case.

Adult↗
PubMed1988

A frequent factor XII gene mutation in Hageman trait.

An additional TaqI restriction site was mapped in intron 2 of the factor XII gene. The site was found only in subjects with total or partial factor XII deficiency and thus represents the true gene lesion or a very tightly linked restriction fragment length polymorphism. The altered gene identified by this marker is present in four (three heterozygotes and one homozygote) of five unrelated Hageman trait subjects from different Italian regions. In the homozygous state the altered gene gives rise to a very marked reduction of factor XII activity. No deletion was found in the deficient factor XII genes.

Blotting, Southern↗
PubMed1979

Effect of factor XII deficiency on pregnancy and parturition.

The clotting parameter of a primigravida with factor XII deficiency was studied during her third trimester of pregnancy, labor and post-partum; and compared with those of her newborn male infant. Sharp increases in factors VII, VIII, IX, X and moderate increases in factors II and XI were documented during pregnancy and at labor. All factors had returned to normal or near normal levels 24 hours after delivery. Factor XII remained at 0.0 level throughout. In the infant the clotting factor levels reflected depression of vitamins K-dependent factors II, IX, and X and a factor XII level of 40.0%. No undue bleeding was noted in the mother at delivery or placental separation, and no bleeding manifestation was apparent in the infant. These findings suggest that factor XII does not play a major role in triggering or modulating the course of normal labor, nor is its absence necessarily associated with bleeding complications during parturition or placental separation.

Adult↗
PubMed1989

[Moderate deficiency of Factor XII associated with postoperative deep venous thrombosis].

The interrelationship between factor XII deficiency (Hageman trait) and thrombosis is well known. A case of moderate factor XII deficiency (activity, 30%) associated to deep vein thrombosis, which occurred in the popliteal region of the left lower limb after abdominal surgery, is reported. The deficit was found in 4 family members of the three generations studied, and all of them showed a close interrelationship between factor XII activity and kallikrein levels. Prolonged APTT was found in 3 of the 4 affected subjects. A multiallelic model is suggested to explain the genetic transmission of this impairment.

Aged↗
PubMed2001

[Ischemic stroke in a patient with factor XII (Hageman) deficiency].

Unlike most other coagulation factor deficiencies, usually associated with abnormal bleeding, lack of factor XII (Hageman) can result in thromboembolic events as a result of a deficient fibrinolytic system. We report a patient with an ischemic stroke and factor XII deficiency, a rare hereditary disorder. The optimal therapy for these uncommon disorders is not well established, but they probably require long term anticoagulation to prevent subsequent thrombotic events.

Aged↗
PubMed1990

The increased rate of activation of factor XII in late pregnancy can contribute to the increased reactivity of factor VII.

The amidolytic activity of enzymes derived from factor XII (XIIa) was 3-fold higher in plasmas collected during pregnancy than from control subjects. Factor VII coagulant activity (VIIc) and XIIa increased in both kinds of plasmas on incubation on ice for 24 h (cold activation). These increases could be attributed to the decreased potency of C1 inhibitor (C1INH). However, variations in the concentration of C1INH and of factor XII could not explain the differences in VIIc and in XIIa between late pregnancy and control plasmas following cold activation under the same conditions. It is concluded that in vitro the increased amount of contact surface in the late pregnancy plasma promotes a higher rate of generation of XIIa and consequently a higher rate of activation of factor VII. The increased amount of contact surface could also be responsible for the increased concentration of XIIa in non-treated plasma from late pregnancy and could contribute in vivo to the higher reactivity of factor VII in this condition.

Amides↗
PubMed1992

O-linked fucose is present in the first epidermal growth factor domain of factor XII but not protein C.

Epidermal growth factor (EGF) domains are found in many proteins, particularly those of the coagulation/fibrinolytic system. We and others have demonstrated that tissue plasminogen activator (t-PA) and prourokinase are modified by the attachment of fucose to equivalent threonine residues within their EGF domains. Factor XII and protein C each contain two EGF domains; in both proteins, the EGF domain nearest the N terminus has a threonine residue in a position homologous to that which is fucosylated in t-PA. In protein C, this site is 3 residues from the position of another post-translational modification, beta-hydroxylation of Asp-71. We isolated peptides containing these sites to determine, primarily by mass spectrometric analysis, the presence of O-linked fucose and/or beta-hydroxyaspartate. We found that factor XII is fully fucosylated at Thr-90. Protein C is unmodified at the equivalent site (Thr-68) and is completely beta-hydroxylated at Asp-71. It has been recently reported that the first EGF domain of human factor VII has O-linked fucose at the equivalent position (Ser-60) (Bjoern, S., Foster, D. C., Thim, L., Wiberg, F. C., Christensen, M., Komiyama, Y., Pedersen, A. H., and Kisiel, W. (1991) J. Biol. Chem. 266, 11051-11057), while it is unmodified at Asp-63 despite having the consensus sequence for beta-hydroxylation at the latter site. These observations raise the possibility that O-linked fucosylation and beta-hydroxylation of EGF domains are mutually exclusive post-translational modifications.

Amino Acid Sequence↗
PubMed1992

A female hemophilia A combined with hereditary coagulation factor XII deficiency: a case report.

A 2-year-old Japanese girl with easy bruising and arthropathy was demonstrated to have severe hemophilia A (Factor VIII activity: less than 0.01 U/ml). She had normal 46XX karyotype. Her brother also had hemophilia A, and her mother and grandmother seem to be hemophiliac carriers. Additionally, activated partial thromboplastin time (APTT) of the patient was disproportionately prolonged and there were reduced levels of coagulation factor XII in the patients and members of the maternal trait which are compatible with heterozygous factor XII deficiency. Her father had both normal factor VIII and factor XII levels. Southern blotting analysis of genomic DNA from the propositus and family members with factor VIII and factor XII DNA probes revealed no gross alterations. This patient represents a female hemophilia A combined with heterozygous factor XII deficiency. Nonrandom inactivation of a normal X-chromosome (extreme lyonization) may be the basis for the expression of hemophilia A in this female patient.

Blood Coagulation↗
PubMed1984

Factor XII deficiency in a man with gout and angioimmunoblastic lymphadenopathy.

A patient with factor XII deficiency, gout, and angioimmunoblastic lymphadenopathy (AIL) was seen initially for an acute myocardial infarction, gout, and unexplained urticaria. The patient eventually was found to have AIL and a prolonged partial thromboplastin time. There was no evidence of a circulating anticoagulant. A factor XII deficiency (Hageman factor) was discovered. The coexistence of a factor XII deficiency, AIL, and gout in the same person raises some interesting questions regarding the basic mechanisms of the inflammatory process.

Factor XII Deficiency↗
PubMed1985

Activation of factor XII and prekallikrein with polysaccharide sulfates and sulfatides: comparison with kaolin-mediated activation.

The activation of Factor XII and prekallikrein by polysaccharide sulfates and sulfatides in the presence of high-molecular-weight (HMW) kininogen was studied, and compared with the kaolin-mediated activation reaction. Among a variety of artificially-sulfated polysaccharides and native polysaccharide sulfates, amylose sulfate (M.W.= 380,000 and sulfur content, 19.1%) and sulfatide were found to have the most efficient ability to trigger the activation of prekallikrein by Factor XII. The effects of these two kinds of negatively-charged surfaces on the following three activation reactions were compared; the activation of prekallikrein by Factor XII (reaction 1), the activation of Factor XII by kallikrein (reaction 2) and the activation of prekallikrein by Factor XIIa (reaction 3). All three reactions mediated by the selected surfaces were strongly accelerated by HMW kininogen and its derivatives, kinin-free protein and fragment 1.2-linked light chain, like the kaolin-mediated activation. However, this accelerating effect of HMW kininogen on the amylose sulfate- and sulfatide-mediated activations (reaction 1) was diminished after treatment with fluorescein iso-thiocyanate, whereas the effect on the kaolin-mediated activation was not influenced by fluorescein-labeling. In addition, reaction 2 mediated by amylose sulfate and sulfatide was extremely slow even in the presence of HMW kininogen, and the results also differed from those with kaolin. The sulfatide-mediated activation of reaction 1 was not inhibited by fragment 1.2 (His-rich fragment), which is released from HMW kininogen by the action of kallikrein, and is known to be a potent inhibitor of the kaolin-dependent activation. These results indicate that the mechanisms responsible for surface activation triggered by soluble amylose sulfate, sulfatide micelles and kaolin differ from each other as regards the molecular interaction with the contact factors.

Animals↗
PubMed1981

Tobacco, cocoa, coffee, and ragweed: cross-reacting allergens that activate factor-XII-dependent pathways.

A glycoprotein antigen has been isolated from cured tobacco leaves (TGP-L) Nicotiana tabacum) and from cigarette smoke condensate (TGP-CSC) to which approximately one-third of human volunteers, smokers and non-smokers, exhibit immediate cutaneous hypersensitivity. TGP-L and TGP-CSC contain polyphenol haptens that activate the factor XII (Hageman factor) dependent pathways of coagulation, fibrinolysis, and kinin generation in normal human plasma. The purpose of this communication is to describe the isolation antigens from cocoa powder (Theobroma cacao), ground coffee (Coffea arabica), and ragweed (Ambrosia eliator) pollen that are immunologically cross-reactive with TGP-L and TGP-CSC, contain similar polyphenol haptens, and are capable of activating factor-XII-dependent pathways in normal human plasma.

Allergens↗
PubMed1992

Contact system dependent fibrinolytic activity in vivo: observations in healthy subjects and factor XII deficient patients.

The contribution of activation of the contact system to activation of the fibrinolytic system in vivo was investigated in healthy volunteers and in factor XII deficient patients. The plasminogen activating activity in normal plasma was only partially blocked (for 77%) with specific antibodies to tissue-type plasminogen activator (t-PA) and urokinase-type plasminogen activator (u-PA). The residual activity could be quenched by a monoclonal antibody that inhibits factor XII activity and was not present in patients with a factor XII deficiency. The formation of plasmin upon the DDAVP stimulus as reflected by circulating plasmin-alpha 2-antiplasmin (PAP) complexes was lower in factor XII deficient patients than in healthy volunteers. These results indicate that in vivo the plasminogen activating activity is partially dependent on activation of the contact system. This fibrinolytic activity is impaired in factor XII deficient patients which may explain the occurrence of thromboembolic complications in these patients.

Adult↗
PubMed1985

[Hageman factor deficiency (factor XII)--hemorrhage or thrombosis?].

Four generations of a kin with congenital Factor XII deficiency were examined for coagulation and fibrinolysis, with the homozygous female carrier of features with a Factor XII below 1% also revealing certain indications of a disturbed fibrinolysis. The other members of the family had to be evaluated as heterozygous ones, showing values of Factor XII between 40 and 60%. The findings are discussed by referring to data from literature.

Blood Coagulation Tests↗
PubMed1987

Acetylcysteine in rats: inhibition of activation of prekallikrein and factor XII--protection against dextran-induced blood pressure fall.

Acetylcysteine (AC) injected intravenously into rats (200 mg/kg) had no effect on blood pressure, but significantly inhibited dextran-induced (40 mg/kg) blood pressure fall. Injection of AC also reversibly blocked the activation of prekallikrein (PK) normally obtained in plasma incubated with acetone. Kallikrein was assayed as plasminogen activator, S-2302 amidase and BAEe esterase. Also the activation of factor XII to factor XIIa, assayed as prekallikrein activator, was strongly inhibited in AC-treated rats. It is suggested that the partial blockade of dextran-induced shock is correlated with an inhibition of activation of PK and factor XII. Previous experiments had demonstrated an extensive, but reversible in vitro inhibition of human plasma kallikrein by AC. In view of such data it is concluded that the present results obtained with AC in rats are probably due to an inhibition of plasma kallikrein and its activation of factor XII.

Acetylcysteine↗
PubMed1979

Acquired factor XII Deficiency in a patient with nephrotic syndrome.

A patient with nephrotic syndrome and an acquired factor XII deficiency associated with a factor XII-like procoagulant activity in the urine was investigated. The urinary protein with procoagulant activity was isolated and comparative investigations revealed similar properties to plasma factor XII. It is suggested that the acquired coagulation defect may result from an insufficient biosynthetic capacity to compensate for the loss of factor XII in the urine.

Adult↗