bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conditions Affecting the Responses of Human Platelets to Epinephrine
Authors: Keraly Chantal Lalau , Kinlough-Rathbone Raelene L , Packham Marian A , Suzuki Hidenori , Mustard J Fraser 
Published: June 2018

SummaryConditions affecting the responses of human platelets to epinephrine were examined. In platelet-rich plasma prepared from blood anticoagulated with hirudin or PPACK (D-pheny- lalanyl-L-prolyl-L-arginine chloromethyl ketone), epinephrine did not cause shape change or aggregation. In a Tyrode-albumin- apyrase solution containing a concentration of Ca2+ in the physiological range, and fibrinogen, epinephrine in concentrations as high as 40 μM did not induce platelet shape change, caused either no primary aggregation or very slight primary aggregation, and did not induce thromboxane formation, release of dense granule contents, or secondary aggregation. In contrast, in citrated platelet-rich plasma, epinephrine induced two phases of aggregation. This is not attributable to the generation of traces of thrombin since the same effects were evident when blood was taken into a combined citrate-hirudin anticoagulant or a combined citrate-PPACK anticoagulant. In a modified Tyrode-albu- min-apyrase solution containing approximately 20 μM Ca2+, 1 mM Mg2+, and fibrinogen, epinephrine induced extensive aggregation after a lag phase, but no primary phase was evident; thromboxane formation and release of dense granule contents accompanied the aggregation response. These responses were also observed when PPACK was included with the acid-citrate- dextrose anticoagulant, and in the washing and resuspending fluids. In the presence of aspirin or the thromboxane receptor blocker BM 13.177 a few small aggregates were detected by particle counting and by scanning electron microscopy; with the latter inhibitor, the platelets in the aggregates retained their disc shape; secondary aggregation and the responses associated with it did not occur. Thus thromboxane A2 formation is not necessary for the formation of these small aggregates, but is required for extensive aggregation and release. As with other weak agonists, the close platelet-to-platelet contact in the low Ca2+ medium appears to be necessary for full secondary aggregation. Omission of fibrinogen from the low Ca2+ medium prevented both primary and secondary aggregation in response to epinephrine. An antibody (10E5) to the glycoprotein Ilb/IIIa complex was completely inhibitory in the presence of fibrinogen. Thus the response of human platelets to epinephrine is influenced by the concentration of Ca2+ and the presence of fibrinogen in the medium in which they are suspended.
Relative Sensitivity of Different Tests in the Detection of Low Titer Lupus Anticoagulants
Authors: Lesperance B , David M , Rauch J , Infante-Rivard C , Rivard G E 
Published: June 2018

SummaryLupus anticoagulants (LA) and anticardiolipin antibodies have been strongly associated with recurrent abortion and fetal death. Because steroids have been reported to improve the fetal outcome of LA associated pregnancies, presumably by decreasing the levels of LA, it becomes desirable to have a simple and reliable test to monitor the levels of the putative antibody. To this effect, we assessed the capacity of the following coagulation tests to detect the presence of LA in serial dilutions of patient plasma with pooled normal plasma: kaolin clotting time (KCT), tissue thromboplastin inhibition test (TTIT), dilute Russell Viper venom time (DRVVT) and activated partial thromboplastin time with standard and high concentrations of phospholipids (SC and HCAPTT). All samples were also evaluated for the presence of anticardiolipin antibodies with an ELISA. The KCT was able to detect LA at a much greater dilution in normal plasma than any of the other clotting assays. The ELISA was comparable to KCT in its ability to detect high dilutions of LA.
Von Willebrand Factor and Mitral Valve Prolapse
Authors: Froom P , Margulis T , Grenadier E , Palant A , David M , Aghai E 
Published: June 2018

SummaryThe levels of von Willebrand factor (vWF: Ag) were measured in 27 patients with mitral valve prolapse (MVP) and compared to 27 age matched controls. Decreased levels of vWF:Ag (<80%) were found in 59% (16/27) of those with MVP compared to only 7% (2/27) of the controls (p <0.001). Mean vWF: Ag levels were also significantly lower in those with MVP (68 ± 30% versus 100 ± 23%, p <0.001). In those with MVP and congestive heart failure secondary to ruptured chordae tendineae, however, the mean level of vWF:Ag was not significantly different from control values (95 ± 32). There was an increased incidence of recurrent nose bleeds in those with MVP and low levels of vWF: Ag. We conclude that there is a relationship between MVP and low levels of vWF:Ag which may explain the increased incidence of epistaxis in such patients. Increased release of vWF: Ag in those with MVP and concomitant congestive heart failure may account for the normal levels found in this subgroup.
Plasminogen Activators in the Intestine of Patients with Inflammatory Bowel Disease
Authors: de Bruin P A F , Crama-Bohbouth G , Verspaget H W , Verheijen J H , Dooijewaard G , Weterman I T , Lamers C B H W 
Published: June 2018

SummaryPlasminogen activators were determined in intestinal tissue, obtained after surgery from patients with Crohn’s disease and ulcerative colitis, and compared with normal intestinal tissue from colorectal cancer patients.The activity and quantity of tissue-plasminogen activator (t-PA) was found to decrease with the severity of inflammation in the patients with inflammatory bowel disease. Urokinase (u-PA) activity, however, was not changed compared with controls or in relation with severity of inflammation. In contrast, the level of u-PA antigen was found to be increased significantly in the inflammatory bowel disease tissues and was also related with severity of inflammation. The difference between u-PA activity and antigen in inflammatory bowel disease tissue could be attributed to an increase in inactive pro-u-PA and u-PA-inhibitor complexes.This increase in u-PA and the concomitant decrease in t-PA, are similar to those found in premalignant colonic adenomas, and might be related to the known increased cancer risk in inflammatory bowel disease.
The Effect of Enzymatic Removal of Sialic Acids on the Functional Properties of Protein C
Authors: Hau Lena , Salem Hatem H 
Published: June 2018

SummaryThe effect of enzymatic removal of sialic acid residues on the functional properties of human protein C was examined. The rates of activation of native and asialo protein C were identical using either the thrombin thrombomodulin complex or the snake venom activator, protac. Desialylated activated protein C (APC) was, two-three-fold more active than native protein C, both as an anticoagulant and in its ability to hydrolyze chromogenic substrates. The potentiating effect of the desialylation was confirmed by initially fully activating protein C followed by the desialylation process. In these studies, a two-three-fold enhancement in the activity of the protein was observed which paralleled the extent of the desialylation. The activity of asialo-protein C was completely abolished by monoclonal and polyclonal antiprotein C antibodies, confirming that the effect was mediated by APC. Our studies suggest that the sialic acid component of protein C is not essential for the expression of APC activity but may act to modulate the function of the protein.
The Effect of Human Recombinant Tissue-Type Plasminogen Activator on Clinical and Laboratory Parameters of Hemostasis and Systemic Plasminogen Activation in the Dog and the Rat
Authors: Bloom John C , Sellers Teresa S , Gries Gary C , Wheeldon Eric B , O'Brien Susan R , Lewis Hugh B 
Published: June 2018

SummaryThe effect of human recombinant tissue-type plasminogen activator (rt-PA) on parameters of hemostasis and systemic plasminogen activation was studied in the dog and rat. Effects on screening coagulation times, fibrinogen concentration, fibrin/fibrinogen degradation products, and plasminogen and α2-anti- plasmin (α2-AP) activities in plasma were examined following single bolus injections of 0.5-5.0 mg/kg, single and repeated 3 hr infusions of 0.75-7.5 mg/kg and 24 hr infusions of 6.0 and 30.0 mg/kg administered intravenously to dogs. Rats receiving single or 14 daily injections of 5.0-30.0 mg/kg i.v. were similarly monitored. Systemic fibrinogenolysis (>50% decrease in fibrinogen, plasminogen or α2-AP values) was observed in dogs receiving ≥1.0 mg/kg as a bolus, ≥3.75 mg/kg (20.8 μg or 1.19 × 104 IU kg−1min−1) as a 3 hr infusion and >6 mg/kg (4.2 μg or 2.42 × 103IU kg−1min−1) as a 24 hr infusion; and in rats treated with bolus injections of 30 mg/kg rt-PA. Clinical and laboratory indications of impaired hemostasis and bleeding (anemia, prolonged coagulation times and post-mortem evidence of hemorrhage) were associated with these effects, which together were dose-dependent and influenced by the rate of infusion. The incidence of major hemorrhage was variable and limited to animals receiving prolonged (24 hr) or repeated infusions.
Conditions Influencing the Interaction of Asialo von Willebrand Factor with Human Platelets – The Effects of External Ionized Calcium Concentration and the Role of Arachidonate Pathway
Authors: Cattaneo Marco , Mustard J Fraser , Canciani Maria T , Richardson Mary , Federici Augusto B , Mannucci Pier Mannuccio 
Published: June 2018

SummaryWe have studied the interaction of ASvWf with human platelets in PRP and in suspensions of washed platelets containing either physiological or low external ionized calcium concentration [Ca2+]0. In hirudin-PRP or in washed platelets in 1.5-2 mM CaCl2, ASvWf up to 50 μg/ml does not induce platelet aggregation or the release reaction. When [Ca2+]c is decreased by addition of citrate to hirudin-PRP or when no CaCl2 is added to washed platelet suspensions, ASvWf does induce platelet aggregation and the release reaction. In low [Ca2+]0, ASvWf interacts with platelet GPIb to cause primary aggregation of disc-shaped platelets to each other through GPIIb/IIIa, with or without added fibrinogen. This primary platelet aggregation leads to thromboxane A2 formation and secondary aggregation and the release reaction. With [Ca2+]0 in the physiological range, there is less ASvWf interaction with GPIb, no primary platelet aggregation and no thromboxane A2 formation. The ASvWf-platelet interaction at physiological [Ca2+]0, however, enhances the platelet response to collagen or epinephrine.
Fibrinolysis Resistant Fibrin Deposits in Lymph Nodes with Hodgkin's Disease
Authors: Ádány Róza , Szegedi Andrea , Ablin Richard J , Muszbek László 
Published: June 2018

SummaryExtravasal fibrin deposition is frequently observed within and around tumorous tissues and has been implicated in various aspects of tumor growth. However, no adequate information has been available on the mechanism how intratumoral interstitial fibrin deposits escape a prompt elimination by the fibrinolytic system. In this study we provide immunomorphological evidence showing that fibrin deposits in lymph nodes with Hodgkin's disease are stabilized and made resistant to fibrinolysis by factor XIII (FXIII) of blood coagulation. By double immuno- fluorescent labelling systems fibrin deposits were simultaneously stained for α2-antiplasmin (α2-AP), the main physiological inhibitor of fibrinolysis and in a number of nodular areas they were also labelled for plasmin (ogen). The detection of α2-antiplasmin-plasmin complex-neoantigen (α2-AP-P-Neo) revealed that α2-AP reacted with plasmin, i.e., α2-AP covalently linked to fibrin indeed inhibited intratumoral fibrinolysis. In addition to fibrin deposits FXIII was also found in cellular elements characterized earlier as tumor associated macrophages. These cells were attached to fibrin strands suggesting that they are involved in the intratumoral fibrin formation and might be a source of fibrin stabilizing factor in the tumor stroma.
Induction of Fibrinolysis by Polyanions in Human Plasma
Authors: Klauser Rainer J 
Published: June 2018

SummaryThe fibrinolytic potency of several polyanions was comparatively investigated. Fibrinolytic activity was measured in a whole plasma assay using H-D-Val-Leu-Lys-pNA (S-2251) as chromogenic substrate and by a fibrin plate assay using plasminogen rich fibrin plates.In the chromogenic substrate assay potent fibrinolytic polyanions comprised dextran sulfate, GAGPS, pentosan polysulfate, polyanethol sulfate, 1-carrageenan and i-carrageenan. Chon- droitin sulfates A, B, ‘C, keratan sulfate, ribonucleic acid, k-carrageenan and heparin were weakly fibrinolytic. Hyaluronic acid and lipopolysaccharide from E. coli were inactive.Similar results were obtained when fibrinolytic activity was measured by a fibrin plate assay. All polyanions except lipopolysaccharide produced lysis zones.Induction of fibrinolytic activity in human plasma was shown to be at least partially dependent on Hageman factor. In factor XII deficient plasma no fibrinolysis was induced by any of the polyanions when measured in the fibrin plate assay.In the. chromogenic substrate assay corn Hageman factor inhibitor (CHFI) inhibited the activation of S-2251 cleaving enzyme by GAGPS, pentosan poly sulfate, polyanethol sulfate, heparin, and ribonucleic acid near completely. The activation by dextran sulfate was inhibited by 45%.Heparin, pentosan polysulfate and GAGPS, three poly anions of therapeutic interest were separately compared. In both assays GAGPS proved the most potent activator, while pentosan poly sulfate exhibited 83% and 44% and heparin 32% and 14% of GAGPS fibrinolytic activity in the chromogenic substrate test and the fibrin plate assay, respectively.
Monoclonal Antibodies Against the Heparin- Dependent Protein C Inhibitor Suitable for Inhibitor Purification and Assay of Inhibitor Complexes
Authors: Laurell Martin , Carlson Timothy H , Stenflo Johan 
Published: June 2018

summaryTwo different monoclonal antibodies against the heparin- dependent inhibitor of human activated protein C were produced, using cleaved modified inhibitor for immunization and partially purified inhibitor for screening of the hybridomas, One of the antibodies recognized free and complexed forms of the inhibitor in immunoblotting experiments. The other antibody was used to develop an assay for A PC -PCI inhibitor complexes. Using the assay the formation of complexes was studied in plasma, both in the presence and absence of heparin. The rate of complex formation was similar to that reported previously for the loss of activated protein C amidolytic activity in plasma. The same antibody was also immobilized on Sepharose and used to purify the inhibitor from fresh human plasma. The purified material appeared as two narrowly spaced bands with Mr about 57,000 in SDS-PAGE. The average yield from 1 liter of fresh plasma was 1 mg of inhibitor, The purified inhibitor formed SDS stable complexes with activated protein G and urokinase that could be identified in immunoblots using specific antibodies.
Dysfunctional Activated Protein C (PC Cádiz) in a Patient with Thrombotic Disease
Authors: Sala N , Borrell M , Bauer K A , Viganò-D’Angelo S , Fontcuberta J , Félez J , Rutllant M L 
Published: June 2018

SummaryThe partial characterization of a dysfunctional protein C (PC), provisionally named “PC Cádiz”, in a 45-year-old male patient suffering from recurrent venous thrombosis is described. The only defect found in laboratory assays for haemostasis and hepatic function was a half normal level of both amidolytic and anticoagulant protein C activity, measured by different functional assays that use thrombin-thrombomodulin complex and a snake venom to activate protein C. Protein C antigen was always found to be within normal levels. Two young daughters of the propositus were found to have the same defect. Double-crossed immunoelectrophoresis, performed in the presence and absence of Ca2+ in the first dimension, showed no clear differences between patient and control PC. PC adsorption to barium salts was also found to be normal. Measurement of the PC activation peptide in the barium citrate eluates after PC activation showed no significant differences between patient and 10 normal controls, the concentration of this peptide being very similar to that of PC zymogen in the same eluates before PC activation. These results indicate that this abnormal PC is able to be normally activated by thrombin-thrombomodulin complex but does not exhibit serine protease activity, probably due to a defect in the PC molecule near the active site center.
Production of the Generalized Shwartzman Reaction by Activated Hageman Factor and α-Adrenergic Stimulation
Authors: McKay D.G , Latour J.-G , Lopez Anatalia M. 
Published: June 2018

SummaryInfusion of activated purified Hageman factor and norepinephrine into pregnant rats produces renal glomerular capillary thrombosis identical to the generalized Shwartzman reaction. Activated Hageman factor alone, norepinephrine alone, and inosithin (a substitute for platelet phospholipid) alone, in addition to the combination of inosithin and norepinephrine were incapable of causing the reaction. These studies confirm the evidence that four basic components of the reaction are 1. activation of Hageman factor, 2. platelet phospholipid, 3. ‘‘fibrinolysin inhibition’’, and 4. stimulation of α-adrenergic receptor sites.
Antithrombin
Authors: Dombrose Frederick A. , Seegers Walter H. , Sedensky James A. 
Published: June 2018

SummaryAn evaluation of the mode of action of antithrombin in the temporary inhibition of purified 3.7 S bovine thrombin was made according to traditional enzyme inhibition theory. Using enzyme clotting activity and concentration of active sites synonymously, it was observed that the binding of antithrombin to thrombin followed a second order reaction that could be distinguished into an essentially irreversible phase and a slower, potentially reversible phase. The level of steady state enzyme inhibition depended upon the ratio of the initial concentrations of enzyme to antithrombin. In addition, there occurred a rapid enhancement of enzyme esterolytic activity during the concomitant loss in clotting activity. This enhancement was also observed for acetylated thrombin which had no proteolytic activity. Under high concentrations of antithrombin, this enhancement subsequently deteriorated. A working hypothesis, including equations, for a mutual depletion system is presented to account for the known parameters of enzyme inhibition by antithrombin. We compared the neutralization of thrombin C with autoprothrombin C and found that each enzyme responds to antithrombin according to similar kinetic relationships.
Quantitative Effects of the Reaction between Factor VIII and Factor VIII Inhibitors
Authors: McMillan C. W , Elston R. C 
Published: June 2018

SummaryTo study the effects of factor VIII and factor VIII inhibitor on each other an assay was developed in which inhibitor activity could be directly related to units of factor VIII. Inhibitor activity in units per ml is defined as the number of factor VIII units reduced to 0.01 factor VIII unit by 1 ml inhibitor plasma after incubation for 1 h at 37° C. Whereas factor VIII was destroyed by inhibitor in accord with a double-logarithmic relation between initial and 1-h residual factor VIII activities, final inhibitor activity was found to be inversely proportional to the ratio of initial concentrations of factor VIII to inhibitor. The latter process resembles “dilution”, rather than direct neutralization, of inhibitor by factor VIII. These effects were observed both in the system for inhibitor assay and in more concentrated mixtures of factor VIII and inhibitor sources in vitro. Results of infusion of factor VIII into a subject with classic hemophilia and an acquired inhibitor suggested that in vivo and in vitro effects of factor VIII and inhibitor activities on each other are comparable, if not identical.
Studies on Liver Factors which Exert an Inhibitory Effect on Platelet Aggregation
Authors: Rogowski W , GaŁasiński W , Bańkowski E , Rzeczycki W 
Published: June 2018

SummaryThe inactivating effect of rabbit liver homogenates on platelet aggregation was investigated.The active substances were found in a nonprotein fraction of the liver homogenates. They were separated and identified as nucleotides and nucleosides. It was found that the platelet aggregation inhibiting substances obtained from the liver, inactivated the platelet aggregating factors, such as ADP, thrombin and collagen. Nucleosides and nucleotides were chromatographically separated from the liver homogenates, and their effect examined on the platelet aggregating factors. The probable mechanism of their inactivation and their pathophysiological significance are discussed.
The Action of an Aniline Derivative (AN 162) on Blood Coagulation and on Platelets
Authors: Deutsch E , Lechner K , Moser K , Stockinger L 
Published: June 2018

Summary1. The aniline derivative AN 162, Donau Pharmazie, Linz, Austria, has a dual action on the blood coagulation: an anticoagulant and an coagulation enhancing effect.2. The anticoagulant action may only be demonstrated with high concentrations (over 1 X 10”3 M related to plasma) preferentially in PPP. It is partially caused by an inhibition of the endogenous way of generation of the prothrombin converting principle. In addition it is suggested that it interferes with the fibrinogen-fibrin reaction in a manner not yet understood.3. The coagulant action is caused by a greater availability of platelet constituents at low concentrations of AN 162 (over 1 × 10-4 M) and by the induction of a release reaction at higher concentrations. The platelet factors 3 and 4, serotonin, adenine, and acid phosphatase are released.4. AN 162 inhibits platelet aggregation. This inhibition can be demonstrated by the PAT of Breddin and in the stirred aggregation test of Born. It is more effective to inhibit the collagen-induced and the second phase of the adrenaline-induced aggregation than the ADP induced one. The platelet retention (test of Hellem) is also reduced.5. The action of AN 162 on the platelets is caused by a damage of the platelet membrane which becomes permeabel for both, soluble platelet constitutents and granula.6. AN 162 interferes with the energy metabolism of the platelets. It causes a loss of ATP, and inhibits the key-enzymes of glycolysis, citric acid cycle, fatty acid oxydation and glutathione reduction.7. AN 162 inhibits the growth of fibroblasts without influence on mitosis.
Purification and Properties of the Thrombin-Like Principle of Agkistrodon acutus Venom and Its Comparison with Bovine Thrombin
Authors: Ouyang Chaoho , Hong Jau-Shyong , Teng Che-Ming 
Published: June 2018

SummaryBy means of DEAE-Sephadex column chromatography, Agkistrodon acutus venom was separated into 12 fractions. The thrombin-like activity was concentrated in Fr.10. This fraction was rechromatographed on Sephadex G-200. A single band was found on microzone electrophoresis at pH 7.4. A single boundary with S20, w of 3.82 S, which was almost symmetrical, was observed by ultracentrifugation. The estimated molecular weight is 33,500. The chemical analysis shows that the thrombin-like principle of the venom is a glycoprotein. The specific activity is 13 times higher than that of the crude venom. The optimal pH value of the thrombin-like principle (pH 7.5) of the venom is almost identical with that of the bovine thrombin (pH 7.2). The thrombinlike principle of the venom is not affected by heparin, while the clotting activity of the bovine thrombin is inhibited by heparin. The thrombin-like principle of the venom is much more heat stable than the bovine thrombin.No clot retraction was found with the thrombin-like principle of the venom, while the marked clot retraction occurred after plasma was coagulated with thrombin.Thrombin can activate factor XIII (Fibrin stabilizing factor), while the thrombinlike principle can not.