bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pharmacokinetics of Human Factor IX in a dog with Severe Hemophilia B.
Authors: Gentry P.A. , Thompson A.R. , Forrey A.W. 
Published: May 2019

In preparing a factor IX concentrate with a high yield and low hepatitis and thromboembolic risks, we have tested this material for survival in an in vivo system, the hemophiliac dog. By following the disappearance of radiolabeled, isolated factor IX in addition to the classic clotting assays, data on protein survival and more accurate kinetic parameters were obtained.Crude factor IX concentrate was prepared by batchwise adsorption-elution with DEAE-Sephadex using cryoprecipitate-poor human plasma. Isolated human factor IX was radiolabeled with 125I by chloramine-T without in vitro loss of clotting activity (Thompson, J Clin Invest, in press, 1977). A preparation containing both crude and isolated factor IX was then subjected to filtration (0.22 μm) and lyophilization; clotting and radioactivity were not altered by these steps.Following infusion of the combined preparation into a dog with severe hemophilia B (0% baseline factor IX) 10 post infusion samples were taken over 96 h for determination of radioactivity and factor IX clotting activity. These data were then analyzed by fitting to a two exponential expression using a Marquart non-linear least squares numerical procedure for a two compartment open model. The central volume was 14.5% of the animal’s body weight; the total volume of distribution was 28% with a t 1/2 distribution of 114 min. The t 1/2 elimination was 20 h; the slower phase of elimination (β, or that affected by redistribution) had a t 1/2 of 40 h. Factor IX clotting activity from the crude concentrate closely paralleled radioactivity from the isolated factor IX throughout the 96 h; t 1/2 β was slightly longer from the clotting activity data.
Detection of Antithrombin III /AT-III/ Complexes in “Hypercoagulable” and Hyper-Fibrinolytic States
Authors: Sas G. , Köves Á , Pető I. 
Published: May 2019

As it was previously described, the complex of thrombin-AT-III end “free” /uncomplexed/AT-III can be discerned by a modified crossedimmunoelectro -phoresis method /heparin in agarose/. Further investigations with the same technique showed that activated factor X/Xa/ and plasmin also form complexes with purified AT-III which, Just as thrombin-AT-III complex, migrate slower, than “free” AT-III. On the basis of these observations we assumed a significant increase of the quantity of these AT-III fractions in various “hypercoagulable” and hyperfibrinolytic states, mainly in DIC.Only about one third of patients with chronic DIC displayed significant increase of AT-III complexes in their plasmas. In a few patients with deep venous thromboses a similar increase of complexed AT-III was observed. In cirrhotic patients with low prothrombin level the administered PPSB concentrate brought about a mild DIC with a striking decrease of “free” AT-III concentra -tion but there was no increase of the complexes. Streptokinase therapy did not increase the quantity of the slow moving fractions of AT-III at all, but the concentration of “free” AT-III decreased significantly.A fast in vivo clearing mechanism of the AT-III complexes can be postulated which could account for the absence of a significant increase of AT-III complexes while the “free” AT-III concentration decreases.
High Molecular Weight Fibrin(OGEN) Complexes
Authors: Alkjaersig N. 
Published: May 2019

Plasma fibrinogen, because of catabolism of fibrinogen in vivo, exhibits biochemical heterogeneity, manifested by molecular weight and other differences between the various thrombin clottable moieties. These comprise high molecular weight fibrin(ogen) complexes (HMWFC) ranging in molecular weight from 400,000 to 1,000,000, native fibrinogen (m.w. 330,000) and derivatives of fibrinogen smaller than the native protein (m.s. 260,000 or less). These moieties may be assayed, in plasma as well as in the purified system, by gel exclusion chromatography with immunologic assay of chromatographic effluents by the Technicon Immunoprecipi-tator and mathematical analysis of elution profiles. The coefficient of assay variation for the individual moieties is 7%.Normal control subjects show (mean ± 1 s.d.) 7.7 ± 6.2% (18.4 ± 21 mg%) of plasma fibrinogen in higher molecular weight complex form, 67 ± 10.3% monomeric fibrinogen and 25.8 ± 6.4% fibrinogen first derivative. Values for plasma HMWFC exceeding mean + 2 s.d. of normal (20% or 71 mg%) are classed as abnormal and regarded as demonstrative of enhanced fibrin formation. The hypothesis that enhanced fibrin deposition is associated with the presence of demonstrable pathology, extravascular or intravascular fibrin deposistion or thrombosis, has been validated in several human disease models.
Blood Coagulation in the Horseshoe CRAB (Limulus polyphemus): A Model for Mammalian Coagulation and Hemostasis
Authors: Levin Jack 
Published: May 2019

The amebocyte is the only type of circulating cellin the blood of Limulus. It is a nucleated cell, the cytoplasm of which is packed with granules. The coagulation system of Limulus is contained exclusively within the amebocytes.Furthermore, factors necessary for blood coagulation are localized within their cytoplasmic granules. Cell-free plasma does not clot and is not required for coagulation. Aggregation and disruption of cells follow exposure of amebocytes to foreign surfaces. Endotoxin produces similar changes and in addition, results in coagulation of the blood, following release from amebocytes of the components of the coagulation mechanism.Coagulation, produced by endotoxin, is the result of activation by endotoxin of an enzyme (or series of enzymes) that in turn reacts with the clottable protein. Endotoxin does not react directly with the clottable protein. The rate of the reaction depends upon the concentration of endotoxin.In both Limuli and mammals, disruption of the integrity of the circulatory system or exposure of blood to foreign surfaces results in aggregation of amebocytes or piatelets, with subsequent changes in shape, disruption of granules, and release of cellular constituents into the surrounding environment. Both cells are necessary for hemostasis but in addition, amebocytes are necessary for the coagulation of blood. The presence of the entire coagulation system in amebocytes provides the basis for suggesting that coagulation in animals was initially a cellularly based function. The role of the amebocyte in controlling infection and its reaction to endotoxin suggest that the response of platelets and the blood coagulation system in various mammals to gram-negative infection or endotoxin is a remnant of this mechanism.
Modification of Thrombin-Induced Platelet Aggregation by Estrogen
Authors: Nagasawa H. , Steiner M. , Baldini M. 
Published: May 2019

The effect of estrogens on platelet function has remained a subject of considerable controversy. Neither in vivo nor in vitro studies have yet established a basis for a possible mode of action of this hormone on platelets. Our studies were predicated on previous results obtained by one of us suggesting a direct interaction of estrogens with antithrombin III(AT III), Platelets were isolated by conventional method from freshly drawn blood of volunteers, washed twice with Ca2+-free Tyrode buffer and finally suspended in this medium at a concentration of 4.5 × 105 platelets/mm3. Aggregation was induced by addition of 0.01 units of purified bovine thrombin (390 NIH units/mg protein). Aggregation was immediate reaching a maximum within 1.5-2 min.AT III purified from human plasma (2 U/mg protein) inhibited thrombin-induced aggregation in a predictable, concentration-dependent manner. Addition of 0.06 U AT III produced almost complete inhibition. The inhibiting effect of AT III was found to be related to the platelet concentration. Increasing the latter diminished progressively the effect of AT III on thrombin-induced aggregation.Beta-estradiol also inhibited the AT III effect on thrombin-induced aggregation abolishing it at a concentration of 5 × 10-6M. The minimal concentration of β-estradiol which produced a recognizable effect in this system was 5 × 10-9M. These results indicate a direct effect of estrogen on AT III, modifying the protein in such a way that subsequent interaction with thrombin either becomes impossible or does not lead to the inactivation of the enzyme. In addition a possible neutralization of AT III by intact platelets is suggested from our data.These studies were supported by a contract from the AEC.
Platelet-Mediated Vasoconstriction: Evidence in Vivo
Authors: Baumgartner H.R. , Tschopp Th.B. 
Published: May 2019

Serotonin, PG-endoperoxides and thromboxane A2 - released from platelets by collagen for example - contract vascular smooth muscle in vitro. Platelets adhering to subendothelium in vivo undergo the release reaction. Platelet adhesion to subendothelium and concomitant vasoconstriction were therefore measured morphometrically in cross sections of rabbit iliac arteries which had been fixed by perfusion of glutaraldehyde at 110 mm Hg: (l) At 1.25, 2.5, 5, 10 and 20 min after complete denudation of endothelium by balloon catheter injury; (2)l0 min after partial denudation; (3)l0 min after complete denudation in rabbits made thrombocytopenic by injection of a heterologous antibody against platelets. The non-ballooned iliac artery served as control. In sham operated rabbits the vessel diameter (D) as derived from the length of the internal elastic lamina in cross sections was similar for both iliac arteries. (l)l0 min after denudation - when surface coverage with platelets approached 100 % and aggregation was maximal - D was reduced by 28+2% (mean ± SE, η = 20, 2p < 0.001). At 1.25 or 20 min - when few platelets or only degranulated platelets, respectively, adhered - D of ballooned and control arteries were again similar. (2) Localized platelet adhesion caused localized vasoconstriction. The extent of platelet adhesion and vasoconstriction correlated (r = 0.64, n = 44, 2p < 0.001). (5) In thrombocytopenic rabbits surface coverage with 22±7% platelets was associated with reduction of D by only 10+3%.Thus platelets freshly adhering to subendothelium in vivo appear to induce a transient contraction of medial smooth muscle cells during a few minutes.
Inhibition of Factor XI by Myeloma Protein M.
Authors: Rimon A. , Raz I. , Lahav M. 
Published: May 2019

Waldenstrom’s macroglobulinemia sometimes involves hemostatic disorders. It has been assumed that this may be due to interaction of the myeloma protein with soom blood coagulation factor(s). In the present investigation the sera of seven myeloma patients were studied for a possible interaction between the myeloma protein and clotting factors II, VIM, IX and XI.Normal human plasma was incubated for 30 mi η at 37°C with different dilutions of patients’ serum or of purified myeloma proteins. The ability of this mixture to restore the clotting times of various deficient plasmas was tested by the partial thromboplastin time test.Factor XI activity of normal plasma was substantially inhibited upon incubation with patient’s serum or with purified myeloma protein M. This effect seems to be specific for myeloma protein M since it was neither observed with myeloma proteins G or A, nor with normal IgM. Other coagulation factors investigated so far were not inhibited by myeloma protein M. It is concluded that this protein is specifically affine to factor XI resulting in hindering the latter’s activity.
Evaluation of the Blood Compatibility of Biomaterials by Plasma Kallikrein Derived from Contact Activation
Authors: Becker U. , Fuhge P. , Heimburger N. , Fischer P. 
Published: May 2019

Contact activation is considered as the crucial step to trigger blood coagulation on artificial surfaces. It is characterized by the conversion of proenzymes in plasma to active enzymes. Kallikrein is one of the proteinases which are generated in the course of contact activation. Consequently, its proteolytic activity can be used for monitoring the velocity of contact activation. This is demonstrated by recording the cleavage rate of the synthetic chromogenic substrate Bz-Pro-Phe-Arg-pNA. Polymer surfaces are known to be only weak activators of the contact phase. Therefore, the aim of the study was to elaborate a system sensitive enough to differentiate between various polymer surfaces. Two different approaches are shown to be effective:1, In a one-step assay diluted plasma is incubated with the materials to be tested in the presence of the chromogenic substrate.2. In a two-step assay whole blood or undiluted plasma is extensively incubated with materials before the residual contact activation capacity is determined by addition of ellagic acid.The release of kallikrein is shown tobe specifically surface mediated by using plasma deficient in single clotting factors and by its sensitivity against various inhibitors. The methods were applied to the evaluation of biomaterials of different shape like beads and tubings. The results correspond to those obtained with coagulation tests. Thus the method may provide a useful tool for the development of blood compatible biomaterials.
Demonstration of Antithrombin III in Fresh and Cultured Endothelial Cells from Human Umbilical Cord
Authors: Chan Vivian , Chan T.K. 
Published: May 2019

We have shown by immunofluorescent technique that the distribution of antithrombin III (ATIII) in human tissues was concentrated around the microvasculature of the lungs and kidneys, as well as veins and small arteries of other organs (liver and spleen). It would seem that ATIII is stored and/or synthesized in the endothelial cells similar to Factor VIII-RAG and Plasminogen Activator. Endothelial cells were isolated from human umbilical cord by collagenase and cultured according to Chemethod described by Shearn etal (1977). In freshly isolated endothelial cells, ATIII could be demonstrated by indirect immunof1uorescent technique and radio immunoassay confirmed the presence of 14.8 ng per 106 cells. After 7 days’ culture, the supernatant from 106 cells contained about 15 ng and the cultured cells (106) contained 16.9 ng ATIII. The presence of ATIII in cultured cells was also confirmed by the positive immunofluorescence. Hence the endothelial cells play an active role in preventing thrombosis by the synthesis and liberation of ATIII, the major natural inhibitor of the intrinsic pathway of Coagulation.Reference: Shearn S.A., Peake I.R., Ciddings J.C., Humphrys J. and Bloom A.L. Thrombosis Research, 11, 43, 1977.
Metabolism of Adenosine Diphosphate by Cultured Umbilical Endothelial Cells
Authors: Dosne A.M. , Escoubet B. , Legrand C. , Bodevin E. 
Published: May 2019

Vascular endothelium has been considered to be responsible for the clearance of circulating adenylnucleotides. Endothelial cells were collected from human umbilical veins and as Pnmary cultures. The cells were incubated in Medium 199 pH 7.4, with 8[14C]-ADP 10-5M and the metabolites were separated by thin-layer chromatography from the supernatant and from the cellular perchloric extract.ADP was degraded as an exponential function of time into AMP and then into adenosine, which was the main catabolite found in the medium at 30 min. Adenosine was taken up by the cells at a constant low rate and then transformed into ATP. The rate of ADP degradation depended upon the physical state of the cells and was increased by cell dissociation The half life of ADP was S min in presence of adherent cells and 3 min in presence of col 1agenase-dissociated cells. The ADP clearance increased as an exponential function of cell density but decreased with the culture age (5 up to 13 days).These results suggest that endothelium may control the formation of circulating adenosine, which contributes to local blood flow regulation and to the non-thromboqenic properties of endothelium.
Detective Platelet Surface Markers in Chronic Myeloid Leukemia (CML)
Authors: Vainer H. , Bussel A. 
Published: May 2019

Leukemic platelets (LP) from patients suffering from CML were shown to express altered surface membrane glycopoteins (Vainer s Bussel, 1977, Intern. J. Cancer, 19, 143). The present study wax devoted to the examination of other platelet surface components in 8 patients with CML, before any treatment : i) UDP-Galactose: glycoprotein galactosyl-transferase (GTase) activity, evaluated from the amount of radioactivity incorporated a) into the acid-precipitable material and b) In the labeled soluble reaction products, eluted following autoraduichromatography - and ii) 14C epinephrine (E) binding sites on isolated LP membranes, determined by a filtration procedure.It was found that i) LP can catalyze the transfer of 14C-Galactose from its activated form (UDP-Gal) onto endogenous and exogenous (ovomucoid) acceptors. The transfer reaction in LP was found at a rate 2 to 4 fold greater than in normal platelets (NP), without affecting the values of the apparent Km for UDP-Gal or other kinetic parameters, ii) Isolated membranes from LP specifically bind 14C-E to alpha adrenergic type sites, but the number of receptors for E, available on LP membrane was lower (or present in a cryptic form) than the level reported in NP (Vainer H., 1977, Cell Str. & Function 2, 267).The modulation of both GTase activity level and E receptor number in LP from CML patients could be involved in or correlated with their abnormal function and morphology.
A Chromogenic Factor X Assay with New Standardized Reagents
Authors: Friberger P. , Lenne C. 
Published: May 2019

A recently published method for Factor X (FX) assay (1) utilizing Russel’s Viper Venom (RW) and a chromogenic substrate has been further investigated by testing a large number of parameters, This method has been considered as a suitable method for monitoring coumarol treatment (Bergström et al).The conditions for the activation of FX by purified preparations of the RVV have been studied as well as the conditions for FXa determination with a new chromogenic substrate Bz-Ile-Glu(γ-piperidyl)-Gly-Arg-pNA (S-2337). Both purified factors and normal plasma have been used. The effect of plasma inhibitors as well as the selectivity of the method bas been studied.The reproducibility and stability of the different reagents and standards have been studied and found to be good.The amount of FXa activity obtained from normal human plasma has been titrated with FXa inhibitors of known purity.1) Aurell L. et al, Thromb. Res., 11, 595 (1977)2) Bergström et al, Thromb. Res., 12, 531 (1978)
Plasma Thromboxane B2(TxB2) and Fibrinopeptide A (FpA) in Patients with Thrombosis and During Contact of Blood with Artificial Surfaces
Authors: Davies G.C. , Sobel M. , Salzman E.W. 
Published: May 2019

To study thrombin activity and platelet stimulation during interaction of blood with artificial surfaces, we measured circulating FpA (normal up to 2.3 ng/ml) and TxB2 (normal 0.08-0.32 ng/ml) by radioimmunoassay. 31 of 32 patients referred for phlebography for suspected DVT had elevated FpA (mean 49 ng/ml) but normal TxB2. 23 patients had DVT and the others had ruptured Baker’s cyst, muscle tears, hematomas, and inflammatory conditions. FpA rose further after phlebography (mean rise 34.6 ng/ml); similar changes followed arteriography and cardiac catheterization. Heparinization failed to return elevated FpA to normal. None of the procedures affected TxB2 levels.General surgical operations raised FpA but not TxB2. However intra-aortic balloon pumping elevated TxB2 (max. rise 0.44 ng/ml). In 24 of 29 patients undergoing cardiopulmonary bypass using a bubble oxygenator, TxB2 rose over 0.05 ng/ml within the first 120 min. of bypass (mean rise 0.49 ng/ml, max. rise 2.0 ng/ml). The levels detected imply sufficient in-vivo thromboxane A2 production to cause platelet aggregation and myocardial ischemia from coronary artery constriction. FpA levels were elevated even before bypass, probably because of intravascular cannulae, and did not return to normal despite “adequate” heparinization (judged by Activated Clotting Time), implying continued thrombin activity during bypass.
Potentiation of the Anti-Aggregating Activities of Prostacyclin by Verapamil
Authors: Ikeda Y. , Toyama K. , Hasegawa M. , Yamamoto M. , Watanabe K. , Ando Y. 
Published: May 2019

Prostacyclin (PGI2), which is a potent inhibitor of platelet aggregation formed in vascular wall, is now considered to play a crucial role in the pathogenesis of thrombosis. Evidence was presented in this investigation that a coronary vasodilator, Verapamil (VP), markedly potentiates the anti-aggregating activities of PCI2. VP caused a dose dependent inhibition of serotonin release induced either by thrombin or by A23187 in the absence of extracellular calcium. Addition of 1 mM CaCl2, with A23187 or thrombin partially overcame this inhibition, while 1 mM CaCl2 alone caused no significant release in the absence of A23187 or thrombin. Minimal concentration of PGI2 (supplied from Hoechst Research Instituted West Germany) to cause 50% inhibition of collagen-induced platelet aggregation was 1 nM, while that of VP was 100 μM. Simultaneous addition of 0.125 nM PGI2 and 30 μM VP resulted in complete inhibition of aggregation. Similar synergistic effects between PGI2 and VP were observed in platelet aggregation induced by ADP, arachidonic acid and A23187. 8-(N-N-diethylamino)-octyl 3,4,5-trimethoxybenzoate (TMB-8), a compound recently show to act as an intracellular calcium antagonist (I. Charo, Bioch. Biophy. Res. Comm.), also potentiates the inhibitory effect of PCI2 on platelet aggregation.Our results suggest that an intracellular calcium antagonist may possibly become an unique anti-platelet agent because of its ability to inhibit release reaction and to potentiate the anti-aggregating activity of PGI2.
In Vitro Synthesis of Bovine Prothrombin in a Purified System
Authors: de Metz M. , Vermeer C. , Soute B.A.M. , Hemker H.C. 
Published: May 2019

Coumarin treatment of the cow results in the appearance of a prothrombin precursor (de-carboxyprothrombin) in the blood. We have isolated from bovine liver the enzyme (prothrombin synthase) that is able to convert purified decarboxyprothrombin into prothrombin. Prothrombin synthase is localized in the microsomal fraction and extracted there from with a buffer containing 2% Triton X-100. Further purification of the enzyme was accomplished by column chromatography on Sepharose 4B, DEAE Sephacell and Sephadex G 100. The molecular weight of prothrombin synthase was found to be about 60,000 D. The enzyme activity is defined as the ability to increase the prothrombin concentration at standard conditions and it is measured as a decrease of the clotting time in the one-stage coagulation assay. In the presence of NaH14CO3, radioactive label is incorporated into decarboxyprothrombin, parallel to the generation of prothrombin.After extraction with a suitable organic solvent prothrombin synthase was separated from endogenously bound vitamin K. After extraction the water phase contained the enzyme, the activity of which was completely restored by supplementing the reaction mixtures with vitamin KH2. The organic phase contained the vitamin K as was deduced from U.V.spectra. Prothrombin synthase is dependent on Mn2+ and molecular oxygen and is inhibited by warfarin, Cl-K and Cu2+.