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At least 19 recordsLinked to original sources
PubMed1977

Fibrinogen synthesis in rabbits: effects of altered levels of circulating fibrinogen.

The effects of altered fibrinogen concentrations on fibrinogen synthesis in rabbits were evaluated by determining the rate of appearance of [75Se]selenomethionine (75SeM) in circulating fibrinogen. Fibrinogen levels were maintained at twice normal by infusion of homologous fibrinogen for either 1 or 6 days before the intravenous injection of 20 micronCi of 75SeM, and the rate of appearance of labeled fibrinogen was measured during the subsequent 24 h. In both groups, synthesis was unchanged. Five hours after induction of partial defibrinogenation by the infusion of bovine thrombin, fibrinogen synthesis was increased threefold. Stimulation was not attributable to decreased fibrinogen concentrations; synthesis was increased equally when levels were maintained above normal by infusion of fibrinogen before administration of thrombin. Heat-inactivated thrombin and diisopropylfluorophosphate-inactivated thrombin did not stimulate fibrinogen synthesis. Thrombin produced elevated titers of fibrinogen-fibrin degradation products (FDP-fdp). However, fibrinogen synthesis was not increased in rabbits that had received FDP-fdp from thrombin-treated donors. These data suggest that neither the fibrinogen concentration nor FDP-fdp influenced fibrinogen synthesis.

Animals↗
PubMed1979

The effect of homologous thrombin and fibrinogen degradation products on fibrinogen synthesis in rabbits.

The effect of intravenous infusions of purified homologous FDP and thrombin on fibrinogen synthesis was evaluated in rabbits. De novo fibrinogen production was measured by the rate of incorporation of 75SeM into circulating fibrinogen. After receiving either 100 or 200 NIH U/kg purified homologous thrombin over 1 hr, rabbits demonstrated threefold and fivefold increases in fibrinogen synthesis, respectively. A correlation between the titers of FDP-fdp and the degree of fibrinogen synthesis was evident. Prior administration of epsilon-ACA prevented the accelerated synthesis of fibrinogen induced by thrombin and inhibited the appearance of FDP-fdp in serum. epsilon-ACA did not interfere with normal fibrinogen production. Fibrinogen synthesis was assessed following infusions of FDP prepared by vitro by digestion of rabbit fibrinogen with plasmin and subsequently identified on SDS-polyacrylamide gels. Preparations which contained predominantly stage 2 intermediate (X, Y, D, and E) or stage 3 final (D and E) fragments accelerated fibrinogen synthesis, whereas those containing predominantly stage 1 fragment X did not. Prior treatment with epsilon-ACA did not alter these results. Infusion of the supernatants derived from immunoprecipitation of the FDP by either anti-rabbit fibrinogen antibody or specific anti-human D and E antibodies significantly diminished the enhanced fibrinogen synthesis induced by the unadsorbed materials. These experiments suggest that the accelerated fibrinogen synthesis induced by thrombin is mediated by FDP, with fragments D and E appearing to be the most potent.

Aminocaproic Acid↗
PubMed1975

Fibrinogen ""New York"--an abnormal fibrinogen associated with thromboembolism: functional evaluation.

A 54-yr-old woman presented with a 23-yr history of repeated life-threatening thromboembolism. The presence of a qualitatively abnormal fibrinogen was suggested by the demonstration of delayed and incomplete coagulation of plasma or partially purified fibrinogen by thrombin or Reptilase. Two brothers showed a similar in vitro defect but were clinically not affected. The plasma fibrinogen concentration was 0.50-1.64 mg/ml when estimated by heat turbidity, clottability, or immunologic techniques. The serum contained 80-820 mug/ml of unclottable fibrinogen-related materials even after 24 hr exposure to thrombin. The fibrinogen-related material in the serum showed faster anodal mobility an immunoelectrophoresis than that of normal plasma. Immunodiffusion studies with rabbit antihuman fibrinogen antiserum showed lines of identity between control plasma and the patient's plasma and serum. Studies of the kinetics of thrombin action on fibrinogen demonstrated impaired release of fibrinopeptide A and B and defective polymerization of preformed fibrin monomers. The maximum amount of fibrinopeptide A released by exhaustive treatment with thrombin was similar (per milligram protein) for both the patient's and control fibrinogen. This abnormal fibrinogen varient is tentatively designated fibrinogen "New York"; its possible identity with one of the previously described abnormal fibrinogens has not been excluded.

Aprotinin↗
PubMed1979

[The behaviour of fibrinogen and fibrinogen degradation products in myocardial infarction. Justification of a prognostic index (author's transl)].

The behaviour of fibrinogen and fibrinogen degradation products in 52 patients with myocardial infarction was analyzed with the aim of finding an evolutive prognostic index for these patients. According to the clinical course the patients who developed complications were separated from those who did not develop them; a special distinction was made of those complications classified as being of thromboembolic type. In the same way those patients who died were analyzed differentially from those who did not. When these facts were related to the behaviour of fibrinogen and of fibrinogen degradation products the following facts were observed: 1) There was an increase of fibrinogen which reached its maximum on the 5th and 6th days and which returned to normal limits on approximately the 9th day. The greatest increase was reached in those patients who developed thromboembolic complications, although the study did not allow to establish significant differences between this group and the rest of the cases. A reactive and nonspecific behaviour was suggested. 2) Fibrinogen degradation productes reached its maximum increase during the 48 hours after the myocardial infarction, without significant differences between both groups. Therefore it does not seem that a prognostic and evolutive assessment can be derived from the study of the changes in the fibrinogen time and fibrinogen degradation products in patients with myocardial infarction.

Adult↗
PubMed1978

Studies of fibrinogen metabolism in healthy and hypertensive female subjects with the use of autologous I-125-fibrinogen.

10 healthy female subjects and 15 female patients with essential hypertension were studied with respect to fibrinogen metabolism in a steady state. Autologous I-125-labeled fibrinogen (I-125-fibrinogen) was used as a tracer. Comparison of the results showed that plasma volume, t1/2 of plasma I-125-fibrinogen and fractional catabolic rate (j3p) of plasma fibrinogen (x) were not appreciably different in both groups of subjects, but plasma fibrinogen concentration, x and catabolic flux of x (j3px) (synthesis rate) were significantly higher in hypertensive subjects, whereas extravascular fibrinogen (y) and fractional transcapillary transferrate (j1) of x were significantly decreased in the patients. Further analyses of the data in both groups showed that there were significant correlations between diastolic blood pressure (P) and j1 with a regression equation of 41 = e-0.0285P, between x and j1 with a regression equation of x = 226e-0.939j 1 and between y and j1 with a regression equation of y = 12.6e0.624j 1. These results indicate that the observed decrease of j1 triggered the transition from normal to pathological steady state and is responsible for the altered metabolism and distribution of fibrinogen in hypertensive subjects.

Adult↗
PubMed1978

Characterization of the amino acids of bovine fibrinogen involved in the fibrinogen-thrombin interaction of the blood clotting process. Comparison with the milk clotting process.

Bovine fibrinogen and the Aalpha and Bbeta chains of bovine fibrinogen have been subjected to chemical modification by a number of reagents and the effects of these procedures on the susceptibility of the proteins to thrombin hydrolysis is described. The reagents used were rose bengal (for photo-oxidation), 2-hydroxy-5-nitrobenzyl bromide, N-acetylimidazole, iodoacetic acid and diethyl pyrocarbonate. Evidence is presented which indicates that the tryptophan and tyrosine residues of fibrinogen are not involved to any great extent in the interaction of this protein with thrombin. Modification with iodoacetic acid suggests that methionine residues play a major role in such interactions, but the fibrinogen chains on which the important residues reside remain uncertain. The use of diethyl pyrocarbonate indicates the participation also of histidine in fibrinogen-thrombin interactions and that, whereas the histidine residues of the Bbeta chain are involved to a great extent, it appears that those of the Aalpha chain are not. The similarities which exist between the fibrinogen-thrombin and the kappa-casein-chymosin systems are discussed.

Amino Acid Sequence↗
PubMed1977

Fibrinogen Marburg a new genetic variant of fibrinogen.

A new case of congenital dysfibrinogenemia has been discovered in a 20 year old woman, who suffered from a severe postpartal hemorrhage after the delivery of her first child, followed by episodes of thrombosis. Coagulation studies reveal a prolongation of thrombin time, reptilase time was immeasurable. Thromboplastin time and partial thromboplastin time were slightly prolonged. Low fibrinogen levels were obtained by techniques, which depend on the coagulation velocity following addition of thrombin, while immunological procedures gave slightly diminished values of fibrinogen. Patients's fibrinogen had a moderate inhibitory effect on the fibrin formation in normal plasma. However, inhibitors of the fibrinogen-fibrin conversion could not be detected. Coagulation factors were normal, fibriolysis as well. The cause of the coagulation disorder was found to be a defect of the fibrinogen molecule, leading to an abnormal fibrin polmerization of patient's fibrin monomers. The release of the fibrinopeptides in the paperelectrophoresis was normal. The defect of the fibrinogen molecule did not protect from thrombotic complications. The same defect could be found in the lower scale in patient's father, 4 of her 7 brothers and sisters, and her son.

Adult↗
PubMed1977

A method for the measurement of fibrinolytic activity based on one dimensional diffusion using small glass tubes. II. With special reference to the differences between the use of plasminogen-rich fibrinogen and that of plasminogen-free fibrinogen as the substrates.

The optimal conditions for the measurement of the fibrinolytic factors of plasma were examined using human and bovine plasminogen-rich fibrinogen or plasminogen-free fibrinogen as the substrates using the one dimensional diffusion method. The results were as follows: 1. There was no essential difference found between using human or bovine fibrinogen. 2. The levels of proactivator-plasminogen and plasminogen could be measured while using either plasminogen-rich or plasminogen-free fibrinogen. But, in using the latter, the proactivator-plasminogen level could not be measured, if a final concentration of more than 2,000 Christensen units of streptokinase were employed. 3. When using plasminogen-rich fibrinogen, anti-plasmin(s) and anti-activator(s) could be measured while using urokinase and plasmin, but not while using streptokinase. However, further study should be given to the measurement of the inhibitors, when using plasminogen-free fibrinogen.

Animals↗
PubMed1976

Human platelet fibrinogen: a protein different from plasma fibrinogen.

Fibrinogen has been purified from normal and dysfibrinogenemia Metz plasmas, and from normal and from the patient's platelets. There are differences in the pattern of disc polyacrylamide gel electrophoresis between normal plasma and normal platelet fibrinogens, but the migration of the A alpha chain is similar. The abnormality of the electrophoretic mobility of the A alpha chain of plasma fibrinogen from Metz dysfibrinogenemia is not found in platelet fibrinogen of this patient. This result clearly establishes that platelet fibrinogen is a different protein from plasma fibrinogen.

Adult↗
PubMed1977

Plasma fibrinogen, cholinesterase activity, and anemia: utility of fibrinogen in multiphasic screening and in assessing the activity of diseases.

I present the general pattern relationship between (a) plasma fibrinogen and cholinesterase activity and (b) plasma fibrinogen and hemoglobin, in 250 and 310 hospitalized adults, respectively. Although responses of cholinesterase were often unrelated to fibrinogen, when its activity in plasma was depressed, above-normal fibrinogen concentrations were present in about 90% of the subjects. Further, despite the observed independence of hemoglobin and fibrinogen concentrations, whenever frank anemia was present (hemoglobin less than 110 to 120 g/liter), hyperfibrinogenemia was also present in about 75-85% of such anemic patients. Thus, these studies affirm that fibrinogen determination would be an appropriate component of tests on hospital admission and also that hyperfibrinogenemia is a very sensitive "acute phase" reactant, and an important reaction for gauging the course of numerous disorders.

Acute Disease↗
PubMed1978

Fibrinogen, fibrin(ogen) degradation products and fibrinopeptide A in pleural effusions. High turnover of fibrinogen in pleurisy.

Fibrinogen, fibrin(ogen) degradation products (FDP) and fibrinopeptide A (FPA) were analysed in pleural fluids from 20 consecutive patients with major effusions of various aetiology. FPA is a short-lived polypeptide which is split off from fibrinogen, whereafter fibrin is formed. FDP are formed through lysis of fibrin or fibrinogen. In 18 patients no fibrinogen could be detected in pleural fluid, whereas two (both having malignant tumours) had detectable but low concentrations. High FPA concentrations, interpreted as reflecting very recent fibrin formation, were found in all pleural fluids except for one case of empyema and one transudate. Plasma concentrations were low in most cases. The same pattern was found with regard to FDP, i.e. exudates showed high concentrations, whereas plasma concentrations were low. The only patient with a transudate showed absence of fibrinogen and low concentrations of FDP and FPA. We interpret our findings as indicative of a high rate of fibrin formation and degradation in pleural exudates and have not found any differences between various types of pleural exudates. Consequently, the findings may illustrate the close association between the coagulation system and inflammatory reactions which may be common to most pleural diseases.

Adult↗
PubMed1977

[Presence of an active fibrinogen--heparin complex in the total blood plasma fraction of plasma fibrinogen degradation products].

It is found by means of different methods (the administration of 35S-heparin, the determination of fibrinolytic activity of blood plasma fractions containing fibrinogen degradation products and fibrinogen--heparin complex, spectral analysis of fibrinogen--heparin complex etc.), that thrombin injection into animals results in the formation of fibrinogen--heparin complex, which is mainly discovered in the fraction of fibrinogen degradation products.

Animals↗
PubMed1976

Reactivity of fibrinogen and fibrinopeptide A containing fibrinogen fragments with antisera to fibrinopeptide A.

Two antisera used in the radioimmunoassay for human fibrinopeptide A (FPA) which appear to have different immunochemical specificities have been tested for cross-reactivity with fibrinogen and with three fragments of fibrinogen which contain the FPA sequence. These fragments were the three-chain, NH2-terminal disulfide knot (N-DSK) produced by CNBr cleavage of fibrinogen, the reduced, carboxymethyl Aalpha chain portion of the N-DSK, and fragment E produced by plasmin digestion of fibrinogen. One antiserum (R-2) showed high specificity for free FPA and less than 2% cross-reactivity with fibrinogen or the FPA-containing fragments. The other antiserum (R-33) possessed a much higher degree of cross-reactivity with the FPA-containing fragments. Synthetic and native fibrinopeptides were found to be indistinguishable in the assay system with either antiserum. As a result of these studies, an hypothesis has been developed concerning the nature of the antigenic determinants on FPA which favor measurement of free FPA and limit cross-reactivity with larger, FPA-containing peptides.

Amino Acid Sequence↗
PubMed1978

Three new cases of an inborn qualitative fibrinogen defect (fibrinogen Oslo II).

An autosomally inherited, qualitative fibrinogen defect is presented. It is associated with prolonged thrombin clotting time, low plasma fibrinogen when assayed by a fibrin polymerization test and large amounts of fibrinogen antigen determinants in the supernatant after clotting. The plasma fibrinogen level was normal when assayed by an immunological technique or by quantitation of insoluble fibrin under conditions in which fibrin polymerization in enhanced. As judged from N-terminal amino acid analyses, fibrinopeptides were split off at normal speed, and the subunit chains of the fibrinogen appeared normal when examined on polyacrylamide gels. The abnormality was not associated with bleeding tendency, and other routine coagulation tests gave normal results. The findings are in accordance with the concept of defective fibrin polymerization.

Adult↗
PubMed1976

Purification of rabbit anti-human fibrinogen antibodies cross reactivity of mammalian fibrinogen.

A simple isolation procedure of highly purified and unaltered rabbit antibodies to human fibrinogen is described. The method used is based upon the preferential adsorption of fibrinogen by barium sulfate at acid pH. After redissolution of the specific precipitate and dissociation of the antigen-antibody complexes at pH 2.4, the fibrinogen is removed by adsorption on barium sulfate, while the antibody protein stays in solution. BaSO4 is eliminated by centrifugation and the supernatant is neutralized and concentrated by ammonium sulfate fractionation (40% saturation). A concentrated solution of specific anti-fibrinogen antibodies is thus obtained; the latter can be used to prepare, by selective immunprecipitation, a fibrinogen free plasma, and to analyze precipitin patterns in cross reacting systems.

Animals↗