Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.6 (thromboplastin)
 13,278 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Infections due to Streptococcus pneumoniae and products from the organism have been associated with alterations in blood clotting and function of platelets. Pneumococci and pneumococcal polysaccharide shortened the clotting times of whole blood, platelet-rich plasma (PRP), and platelet-poor plasma (PPP) in vitro. Clotting times of PPP and PRP from C6-deficient animals were likewise decreased. The bacteria had no effect on the one-stage prothrombin time or the partial thromboplastin time when the organisms were used as activating agents. Platelets aggregated in the presence of pneumococci, but aggregation was prevented by the addition of cyclic adenosine 3', 5'-monophosphate (cAMP). Furthermore, cAMP corrected the shortened clotting time of PRP in the presence of pneumococci. The clumping and release of polymorphonuclear coagulant that was induced by pneumococci was not prevented by cAMP. Thus, pneumococci exert several dose-dependent thromboplastic effects: (i) release of platelet thromboplastic substances; (ii) a direct thromboplastic effect; and (iii) release of polymorphonuclear coagulant.
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PMID:Effect of pneumococci on blood clotting, platelets, and polymorphonuclear leukocytes. 0 Mar 31

Gastric lesions occurred spontaneously and were increased in number by seven hours of restraint stress in rats with portal vein constriction (PVC). Vagotomy and pyloroplasty protected the congested stomach from erosion formation with stress. Major weight loss occurred two days after PVC, but not thereafter. Platelet counts were decreased in intact and splenectomized rats with portal hypertension, but prothrombin time, partial thromboplastin time, and fibrinogen were unaffected, and histological stains failed to demonstrate thrombin in the gastric blood vessels. The oxygen pressure (PO2) of the gastric luminal fluid was decreased at day 2, but was normal at day 4 after PVC. Hypersection of acid and abnormal acid equilibration were not observed in the stomach. Gastric congestion, weight loss, and possibly portasystemic shunting of blood contributed to the higher incidence of gastric erosions with portal hypertension.
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PMID:Portal hypertension and gastric lesions in the rat. 0 51

The macromolecular breakdown products of fibrinogen are known mainly for their inhibitory effect on the clotting of fibrinogen by thrombin. This inhibitory effect is due to interference with both the proteolytic action of thrombin and the polymerization of the fibrin monomers. However, the action of these products is not limited to these effects. They can on the one hand inhibit the consumption of Factors II and XIII and promote the inactivation of Factor VIII by thrombin. On the other hand, they can potentiate the activation of prothrombin in purified systems via the intrinsic pathway. The incidental observation was also made that Factor IXa and or Factor Xa inactivate Factor VIII. As substrates of both thrombin and plasmin the large fragments protect these two enzymes from spontaneous inactivation, while at the same time they inhibit their respective proteolytic activities. Contradictory results were obtained regarding their effect on platelets. The micromolecular (dialyzable) breakdown products prolong the thrombin, prothrombin, and partial thromboplastin times of plasma and retard the generation of the intrinsic prothrombin activator. They can also potentiate the effects of biologically active peptides and amines on the smooth muscles and on vascular permeability.
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PMID:Physiological effects of the plasminolytic derivatives of fibrinogen. 0 46

The in vitro effects of N-3-(1-benzyl-cycloheptyloxy)-propyl-N,N-dimethylammonium-hydrogenfumarate (bencyclan) on clotting, fibrinolytic and platelet function test were investigated by adding the drug to normal human plasma. An anticoagulant activity, mainly of an antithromboplastin nature (directed against later stages of intrinsic thromboplastin formation and against tissue thromboplastin), was observed, while thrombin phase was unaffected. No effect was found in the fibrinolytic system tested (euglobulin lysis, UK-activated fibrinolysis, "hanging clot" method). The drug, although capable of aggregating platelets by itself at very high concentrations, showed a striking inhibitory effect, over a wide range of concentrations, both on platelet aggregation induced by ADP, epinephrine or collagen and on platelet adhesiveness to glass or collagen. Clot retraction was also clearly inhibited. PF3 availability was influenced with a peculiar two-phase behaviour dose-dependently. High concentrations showed a promoting action, while the lower were obviously inhibitory. It is suggested that the effects on platelet function may be due to an influence of the drug on cell membrane.
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PMID:In vitro effects of bencyclan on coagulation, fibrinolysis and platelet function. 1 70

In the rabbit the application of a non-lethal, sleep-inducing dose of bromisovalerianyl carbamide (0.5 g/kg body weight) causes an activation of the coagulation system. This activation is manifested by shortened thrombin and partial thromboplastin times and a decrease of fibrinogen concentration and Factor V activity. In contrast, pentobarbital sodium at a dose (62.5 mg/kg) which causes the same changes in arterial partial oxygen pressure and arterial pH does not influence the coagulation system. The bromocarbamide-induced changes in the coagulation system are not to be considered as a result of hypoxia and acidosis but seem to be caused by early endothelial and tissue lesions which result in the release of procoagulatory substances. In healthy test persons a single dose of 1.5 g bromisovalerianyl carbamide has no demonstrable influence on the system of hemostasis.
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PMID:The activation of intravascular coagulation by bromocarbamide. 1 52

Human alpha-thrombin, the thromboplastin activation product of prothrombin with high clotting and esterase activity, was produced from Cohn Fraction III paste. The procedure started with 0.4 to 3.2 kg of frozen paste and was completed in 2 or 3 days. Some 23 g of thrombin were recorded for 65 quantitated preparations made from 11 lots of Fraction III paste. These preparations were obtained at protein concentrations of 3.9 +/- 1.3 mg/ml with a yield of 340 +/- 110 mg/kg of paste, which represented 48 +/- 14% of the clotting potential extracted as prothrombin. They had specific clotting activities of 2.8 +/- 0.4 U.S. (NIH) units/microng of protein and titrated to 88 +/- 8% active with p-nitrophenyl-p'-guanidinobenzoate (NPGB). Those (N - 29) examined by labeling with [14C]diisopropyl phosphorofluoridate (iPr2P-F) and electrophoresing in sodium dodecyl sulfate (SDS)-polyacrylamide gels were found to contain only (N = 4) or predominantly alpha-thrombin (97 +/- 3%) and corresponding amounts of ists degradation product, beta-thrombin (2.6 +/- 3.1%). No plasmin(ogen), prothrombin complex factors (II, VII, IX, IXalpha, X, Xalpha), or prothrombin fragments were detected in representative preparations. As produced in 0.75 M NaCl, pH approximately 6, thrombin was stable for approximately 1 week at 4 degrees and for greater than 1 year at less than or equal to 50 degrees; freeze-dried thrombin stored at 4 degrees for greater than 1 year displayed stable clotting activity and no vial to vial variation, permitting its use for reference purposes. Human thrombin generated by Taipan snake venom activation was compared with that produced by rapid thromboplastin activation: after treatment with [14C]iPr2P-F, greater than 95% of the label in both thrombins migrated at the same rate during electrophoresis in SDS; identical pairs of NH2-terminal residues were released in three consecutive Edman degradation cycles.
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PMID:Human thrombins. Production, evaluation, and properties of alpha-thrombin. 1 8

After observing that lavage of the stomach with alkaline solutions has a beneficial effect on the control of gastric hemorrhage, we examined the platelet and coagulation factor activities under conditions of lower and elevated pH. The results showed that change of the pH from acidosis to 7.0 and even to slight alkalosis induces platelet aggregation, platelet calcium and serotonin release, as well as platelet factor II availability. The prothrombin and partial thromboplastin times approached normal levels, whereas the fibrinogen level did not change significantly. The results obtained may serve as an explanation for the control of the intragastric bleeding in patients treated by maintenance of their gastric pH at 7.0.
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PMID:The effect of pH on platelet and coagulation factor activities. 2 78

One of the problems concerning the continuous pH-monitoring technique is whether the relationship between pH measured by the electrode and pH in central and/or capillary fetal blood is constant. To test to what extent a fibrin clot deposited on the pH-electrode influenced the recorded value and the sensitivity of the electrode, the following in vitro study was performed. Fibrin was deposited on the pH-electrode by means of thromboplastin and fibrinogen, or by thromboplastin and whole blood. The deposition of a clot was verified by inspection of the electrode in a microscope. The time for stabilization of the recorded pH-value and the recorded pH-value was measured in standard calibration solutions before and after deposition of the fibrin clot and after decomposition of the fibrin clot by plasmin. FDP was measured in the decomposition solution. From the study it was obvious that the stabilization time of the electrode was considerably influenced by deposition of an "unphysiological" fibrin clot, less so if the clot was deposited by means of whole blood. The recorded pH-value was not influenced.
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PMID:The effect of fibrin deposition on the sensitivity of the continuous monitoring pH electrode and on the recorded pH value: an in vitro study. 3 13

The potential differences in hematologic profiles of blood samples drawn simultaneously from the right utero-ovarian vein and from the upper extremity were investigated in four patients with uncomplicated molar pregnancy in stable obstetric conditions. The patients had undergone no previous chemotherapy and were scheduled for total abdominal hysterectomies. The dominant abnormalities in uterine venous blood were prolongation of thrombin time; shortening of activated partial thromboplastin time; positive protamine sulfate test; and increase in coagulation factors II and VII, with a tendency to low values in factor V. Peripheral samples gave almost parallel results in all altered and normal tests, except in one case with very striking differences in factors II, V, VII and X. Several local and systemic influences are discussed. It is concluded that molar pregnancy seems to have important systemic mechanisms affecting the stability of the blood coagulation homeostasis, which act in addition to those at a local level.
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PMID:Uterine and peripheral hematologic profiles in molar pregnancy. 3 41

A heat-stable humoral substance (coagulopoietin-X) is present in rabbits partially depleted of Factor X, which is capable of raising Factor X levels when injected into recipient rabbits. Rabbits were partially depleted of Factor X by slow infusion of a globulin fraction of goat anti-rabbit Factor X antibody. This resulted in the reduction of Factor X to 40--50% of normal at 1 h and 60--70% of normal at 6 h. No effect was noted on levels of Factors II, V, or VII. Plasma from these animals, when injected into 10 recipients, specifically raised Factor X levels when measured by four different assay: one-stage assay with bovine VII- and X-deficient plasma and Russell's viper venom; one-stage assay with human X-deficient plasma and thromboplastin; chromogenic substrate assay with Russell's viper venom; and an immunologic assay (Laurell technique). No rise was noted in two control experiments in which normal plasma was injected into recipient rabbits from 2 rabbits injected with a globulin fraction of normal goat serum, nor in 12 rabbits injected with plasma from normal rabbits, nor in 5 rabbits injected with boiled plasma from normal rabbits. The rise in biologic activity of 120--150% of base line was significantly greater than the rise in immunologic activity of 114--117% of base line (P less than 0.05) on 3 different days, suggesting the production of a molecule with greater specific activity rather than increased protein synthesis.
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PMID:Humoral factor that specifically regulates factor X levels in rabbits (coagulopoietin-X). 4 Oct 3


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