Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

An investigation was carried out of the effect of decomplementation by either aggregated human gamma globulin (aggHGG) -- activating the classical complement cascade -- or cobra-venom factor (CVF) -- acting through the alternative pathway -- on rat paw oedema induced by various agents. The direct, passive Arthus reaction (DPA) and dextran-and carrageenin-induced oedema were inhibited by both decomplementing measures, whilst serotonin-and formalin-induced oedema remained unaffected. The paw swelling induced by synthetic bradykinin was significantly reduced only by aggHGG, not by CVF. These observations strongly support -- but do not yet prove -- the assumption that complement is involved in the development not only of the DPA but also of the responses to the polysaccharides, dextran and carrageenin in the rat. The partial inhibition of bradykinin-induced paw oedema by aggHGG and not by CVF might be explained by a densensitization or blocking of bradykinin receptors by a peptide derived from the early-reacting complement components (C 1, 4, 2). Investigations of the effect of aggHGG and CVF on blood pressure, haematocrit, partial thromboplastin time, plasmakininogen and kinase activity, leucocytes and thrombocytes indicate that non-complement-dependent factors are unlikely to be involved in the observed inhibition of experimental rat paw oedema.
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PMID:[The effect of decomplementation on model experimental inflammatory responses (rat paw oedema) (author's transl)]. 6 Aug 27

Five commercially available activated partial thromboplastin time (APTT) test systems were compared with the kaolin partial thromboplastin time (KPTT) method to determine sensitivity in detecting minor coagulation defects. All reagent systems detected severe factor VIII-, IX-, and XI-deficient hemophilia. Homozygous states of factor XII deficiency, Fletcher factor deficiency, and high-molecular-weight kininogen deficiency (Fitzgerald trait) also showed abnormally long APTTs by all systems. Of 19 samples from patients with deficiencies of factors XII, VIII, IX, XI, and II ranging from 2.5 to 52%, eight had deficiencies that were not detected by reagent A (ellagic acid); two, by reagent B (ellagic acid); two, by reagent C (kaolin); one, by reagent D (silica); one, by the KPTT method. All deficiencies were detected by reagent E (celite). Heparin effect on plasma was less well detected by reagent A (ellagic acid) than with the other test systems. APTT test systems can vary greatly in their abilities to detect minor coagulation abnormalities.
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PMID:Activated partial thromboplastin time and minor coagulopathies. 42 Jan 68

Bovine high molecular weight kininogen (bHMWK) partially corrects the activated plasma thromboplastin time (aPTT) of Fitzgerald trait plasma which is congenitally deficient in HMWK. The relationship between the structure and activity of HMWK was clarified by studying the effects of different fragments of bHMWK on the aPTT of Fitzgerald-trait plasma. The peptides studied were lys-bradykinin-free HMWK, bradykinin-fragment 1-2-free HMWK, heavy chain, fragment 1-2-light chain, and light chain. All fragments were tested in equimolar concentrations. Bradykinin-fragment 1-2-free HMWK, heavy chain, and light chain have little or no correcting activity upon Fitzgerald-trait plasma aPTr. Fragment 1-2 light chain has the same correcting activity as intact bHMWK, while that of lys-bradykinin-free HMWK appears to be higher. Both fragment 1-2 and fragment 2 inhibit the clotting time of normal human plasma. When compared on a molar basis, fragment 2 is a more active inhibitor than fragment 1-2. When the effects of bovine plasma kallikrein upon bHMWK and hHMWK were studied, it was found that it released kinins from both kininogens. However, while the correcting activity of bHMWK was completely destroyed after 60 min of incubation, that of hHMWK was fully retained. These data suggest that: (a) the active part of bHMWK is comprised of the fragment 1-2 light chain portion; (b) fragment 1-2 or fragment 2 is the binding site to negatively charged surfaces, while the light chain interacts with other components of the surface-mediated reactions; and (c) bovine plasma kallikrein releases kinins, but probably does not cause the release of fragment 1-2 from human HMWK.
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PMID:Relation between structure and correcting activity of bovine high molecular weight kininogen upon the clotting time of Fitzgerald-trait plasma. 42 63

Studies of plasmas from individuals with Hageman trait (factor XII deficiency), plasma thromboplastin antecedent (PTA, factor XI) deficiency, Fletcher trait (plasma prekallikrein deficiency) and Fitzgerald trait (high molecular weight-kininogen deficiency) have revealed the importance of these proteins in blood coagulation. The interactions among them, however, are not fully elucidated. We have studied these reactions by two different approaches. (1) In a purified system, high molecular weight kininogen was absolutely required for activation of PTA by HF and ellagic acid (EA). The yield of activated PTA was proportional to the amount of HF, HMW-K, and PTA in the mixtures, suggesting that these three proteins may form a complex in the presence of EA. (2) In experiments with whole plasma, we took advantage of the adsorption of EA to Sephadex gels. When normal plasma or plasma deficient in HF, PK, HMW-K or PTA was exposed to Sephadex-EA and was separated by centrifugation, each supernatant plasma except that deficient in HF shortened the prolonged partial thromboplastin time (PTT) of HF-deficient plasma. Plasma simultaneously depleted of HMW-K, PK and PTA also shortened the PTT of HF-deficient plasma and of plasma depleted of HF and PK, but had virtually no procoagulant effect upon the PTT of plasma depleted of HF and MHW-K. Thus, exposure of HF in plasma to Sephadex-EA appeared to generate a clot-promoting form of HF in the absence of other clotting factors, but its expression required the presence of HMW-K.
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PMID:Interactions among Hageman factor (HG, Factor XII), plasma thromboplastin antecedent (PTA, Factor XI), plasma prekallikrein (PK, Fletcher factor) and high molecular weight kininogen (HMW-K, Fitzgerald factor) in blood coagulation. 51 54

Asymptomatic identical twins were found to show the prolonged activated partial thromboplastin time, which was corrected by addition of normal, Hageman factor deficient or Fletcher trait plasma but not corrected by Fitzgerald or Williams plasma. The prolonged activated partial thromboplastin time was also corrected by addition of highly purified bovine high molecular weight kininogen but not by low molecular weight kininogen. When total kininogen was measured as the amount of bradykinin released by trypsin on acid treated plasma, only trace amount was detected in Fujiwara and Williams plasmas, although Fitzgerald plasma showed approximately 50% of the total kininogen of normal plasma level. Acetone-kaolin activated amidase activity of plasma kallikrein was not generated by Fujiwara plasma. Substitution with normal plasma in various ratios showed plasma kallikrein activity proportionally to the normal plasma contents. Extrapolation with the values at 120 min after activation gave the prekallikrein content of Fujiwara plasma as 30% of the normal value.
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PMID:Fujiwara trait: the first case of kininogen deficiency in Japan. 51 63

Evidence of developmental evolution of coagulation can be seen when the studies of 10 thriving extremely premature (EPT) infants are compared to normal full-term (FT) infants. The prothrombin time, partial thromboplastin time, and thrombin time all became shorter with increasing gestational age. Fibrinogen levels and platelet counts appear to be comparable to term infant and adult levels. Fibrin degradation products (FDP) of 10 micrograms/ml or less were found in the thriving EPT infants. When compared to healthy full-term infants, there is a definite gestational dependency of anti-thrombin III levels. Factors II and VII appear to be related to intrauterine maturation after the age of viability (24 wk), but factor VII-X complex does not. The contact factors XI, XII, high molecular weight kininogen (Fitzgerald factor), and prekallikrein (Fletcher factor) are all markedly decreased in thriving EPT infants. The mean factor V level is lower than that found in FT infants. This study confirms a gestational age dependency of factor VIII activity. The ratio of factor VIII antigen to factor VIII clotting activity is increased (2.8 vs 1.01 in FT and adults). Thriving small for gestational age (SGA) infants had coagulation studies which were not statistically different from those of thriving EPT infants. The coagulation changes which occurred in severely ill EPT were mainly in the factors which decrease during intravascular coagulation (factors I, V, and VIII). The present study suggests that because of the high antigen to activity ratio seen in thriving EPT infants, a dysfunctional or fetal factor VIII may have been produced. However, the further elevation of this ratio in the severely ill EPT infants is in keeping with a pathologic proteolysis or increased endothelial release of factor VIII antigen.
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PMID:Coagulation studies in extremely premature infants. 52 93

We studied a coagulation abnormality present in 12 members of five kindreds who bruised easily and bled excessively after minor trauma. Their activated partial thromboplastin times were between 32 and 39 seconds (normal, 22.8 to 28.8 seconds). Prothrombin times, thrombin times, platelet-function tests and the levels of factors XII, XI, IX, VIII, prekallikrein and high-molecular-weight kininogen were normal. Within these kindreds inheritance of prolonged partial thromboplastin times followed an autosomal and probably dominant pattern. The prolonged thromboplastin times were corrected by normal plasma and by normal plasma adsorbed with celite, but there was no mutual correction between plasmas of the patients. These subjects shared a common defect in the intrinsic pathway of coagulation that we designate by the proband's surname, Passovoy.
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PMID:The Passovoy defect: further characterization of a hereditary hemorrhagic diathesis. 64 12

We studied a patient being treated with procainamide in whom we observed a high antinuclear antibody titer and prolonged activated partial thromboplastin (PTT), prothrombin (PT), and Stypven times (ST). Serum antibody concentrations against single-stranded DNA were elevated while those aginst native DNA were not elevated, suggesting the procainamide-induced lupus syndrome. Dilution of the patient's plasma with normal plasma failed to correct the PTT and PT, indicating the presence of an inhibitor(s) to blood coagulation. The anticoagulant activity was associated with the IgG fraction of the patient's serum. Addition of purified or partially purified human factors IX, X, VIII, VII, XIa, prekallikrein, high molecular weight kininogen, or phospholipids to the patient's plasma failed to correct the PTT, PT, or ST; however, purified human factor XII and prothrombin corrected the PTT and ST, respectively. These results indicate that production of antibodies directed against antigenic determinants on coagulation proteins can be a manifestation of procainamide-induced lupus erythematosus.
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PMID:Circulating inhibitors of blood coagulation associated with procainamide-induced lupus erythematosus. 71 99

Synthetic procedures have been developed for the preparation of peptides of arginine chloromethyl ketone and applied in the preparation of affinity labels which correspond to the -Pro-Phe-Arg- C terminus of bradykinin, a physiological cleavage site of kallikrein in kininogen. Two such reagents, Ala-Phe-ArgCH2C1 and Pro-Phe-ArgCH2C1, proved to be highly effective as well as selective affinity labels for human plasma kallikrein. For example, Pro-Phe-ArgCH2C1 inactivates plasma kallikrein 50% in 24 min at a concentration of 2 x 10(-8)M, while other trypsin-like proteases are less susceptible in inactivation than kallikrein, differing by a factor of 48 for plasmin and factors of 10(2)-10(5) for factor Xa, thrombin, and urokinase. The affinity of human plasma kallikrein for Ala-Phe-ArgCH2C1 (Ki = 0.078 micron) is about 60 times that for Ala-Phe-LysCH2C1(Ki = 4.9 micron), whereas human plasmin exhibits about the same affinity for the former affinity label (Ki = 1.3 micron) as for the latter (Ki = 0.83 micron). The rate constants for the irreversible step of the affinity labeling reaction, k2, are similar for affinity labels tested with the individual proteases: 0.35 min-1 for plasma kallikrein and 0.18 min-1 for plasmin.
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PMID:Synthesis of peptides of arginine chloromethyl ketone. Selective inactivation of human plasma kallikrein. 72 86

An asymptomatic woman (Ms. Williams) was found to have a severe abnormality in the surface-activated intrinsic coagulation, fibrinolytic, and kinin-generating pathways. Assays for known coagulation factors were nromal while Fletcher factor (pre-kallikrein) was 45%, insufficient to account for the observed markedly prolonged partial thromboplastin time. Plasminogen proactivator was present at 20% of normal levels and addition of highly purified plasminogen proactivator containing 10% plasminogen activator partially corrected the coagulation and fibrinolytic abnormalities but not the kinin-generating defect. This effect was due to its plasminogen activator content. In addition, Williams trait plasma failed to convert prekallilrein to lakkilrein or release kinin upon incubation with kaolin. Kininogen antigen was undetectable. When normal plasma was fractionated to identify the factor that corrects all the abnormalities in Williams trait plasma, the Williams factor was identified as a form of kininogen by its behavior on ion exchange chromatography, gel filtration, disc gel electrophoresis, and elution from an anti-low molecular weight kininogen immunoadsorbent. High molecular weight kininogen as well as a subfraction of low molecular weight kininogen, possessed this corrective activity while the bulk of low molecular weight kininogen functioned only as a kallikrein substrate. Kininogen therefore is a critical factor required for the functioning of Hageman factor-dependent coagulation and fibrinolysis and for the activation of prekallikrein.
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PMID:Williams trait. Human kininogen deficiency with diminished levels of plasminogen proactivator and prekallikrein associated with abnormalities of the Hageman factor-dependent pathways. 120 89


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