bluuebunny/crossref_metadata_2025_split huggingface dataset:
Glycoprotein Ib Has a Partial Role in Platelet-von Willebrand Factor Collagen Interaction
Authors: Aihara Morio , Tamura Ken , Kawarada Ryuko , Okawa Keizou , Yoshida Yutaka 
Published: June 2018

SummaryThe adhesion of human fixed washed platelets (FWP) to collagen was decreased after treatment with Serratia marcescens protease (SP), which removed 95% of the glycocalicin from platelet membrane glycoprotein (GP) lb. However, the diminished adhesion of SP treated FWP to collagen could still be increased in the presence of purified von Willebrand factor (vWF). This ability of vWF to increase FWP adhesion to collagen is defined as collagen cofactor (CCo). The adhesion of FWP to collagen was not affected by a monoclonal antibody (MAb) to GP Ilb/IIIa (10E5), that inhibits ADP and collagen induced platelet aggregation. On the other hand, it was decreased by 50% by a MAb to GP lb (6D1), that inhibits ristocetin induced platelet aggregation. Adhesion of FWP in buffer to collagen was completely inhibited by Ricinus communis agglutinin I or concanavalin A, while Lens culinalis agglutinin and wheat germ agglutinin showed 50% inhibition. The FWP adhesion to collagen in the presence of vWF (normal plasma) was unaffected by MAbs to GP Ilb/IIIa (10E5, P2, HPL1) but was decreased to 32-38% by MAbs to GP lb (6D1, AN51, HPL11). A MAb to vWF (CLB-RAg 35), that inhibits ristocetin induced binding of vWF to platelets, decreased the CCo of normal plasma by 70%. The MAb, CLB-RAg 201, that inhibits the binding of vWF to collagen, completely inhibited the CCo of normal plasma. In conclusion, our data suggest that (1) GP lb has a partial role in FWP adhesion to collagen; (2) the binding of vWF to collagen is required for the expression of CCo; (3) CCo is partly mediated through GP lb; but (4) other platelet membrane protein(s) besides GP lb or GP Ilb/IIIa must also be involved in FWP-vWF-collagen interactions.
Decreased Platelet-Free Dopamine and Unchanged Noradrenaline and Adrenaline in Essential Hypertension
Authors: Kjeldsen S E , Gjesdal K , Leren P , Eide I K 
Published: June 2018

SummaryThe content of free-catecholamines in blood platelets is much higher than in plasma and platelet catecholamines must be taken up from plasma, since platelets lack the enzymes for catecholamine synthesis. There is some evidence that platelet catecholamine content under certain circumstances may be an integrated measure of plasma catecholamine concentrations over time. Platelet-free catecholamines were therefore assayed in 18 untreated patients with essential hypertension and in 16 normotensive control subjects. Mean platelet-free dopamine in the hypertensive group was 3.7 ± 0.4 pg/mg platelet weight, i.e. significantly less than the 6.5 ± 0.9 pg/mg found in the normotensive (p <0.005). Platelet contents of noradrenaline and adrenaline did not differ. Decreased platelet-free dopamine and unchanged platelet noradrenaline and adrenaline persisted after adjustment for increased body weight in the hypertensive group. Although the reasons for decreased platelet-free dopamine in the hypertensive group remain unknown, this finding may add to previous result showing facilitated release of granular contents from blood platelets in patients with essential hypertension. Our data do not support platelet levels of free-catecholamines to be a marker of increased sympathetic tone in essential hypertension.
The Influence of Carbohydrate Structure on the Clearance of Recombinant Tissue-Type Plasminogen Activator
Authors: Hotchkiss A , Refino C J , Leonard C K , O'Connor J V , Crowley C , McCabe J , Tate K , Nakamura G , Powers D , Levinson A , Mohler M , Spellman M W 
Published: June 2018

SummaryModification of the carbohydrate structures of recombinant tissue-type plasminogen activator (rt-PA) can increase or decrease its rate of clearance in rabbits. When rt-PA was treated with sodium periodate to oxidize carbohydrate residues, the rate of clearance was decreased from 9.6 ± 1.9 ml min−1 kg−1 to 3.5 ± 0.6 ml min−1 kg−1 (mean ± SD, n = 5). A similar change in the clearance of rt-PA was introduced by the use of endo-β-N-acetyl- glucosaminidase H (Endo-H), which selectively removes high mannose asparagine-linked oligosaccharides; the clearance of Endo-H-treated rt-PA was 5.0 ± 0.5 ml min−1 kg−1. A mutant of rt-PA was produced with an amino acid substitution at position 117 (Asn replaced with Gin) to remove a potential glycosylation site that normally contains a high mannose structure. The clearance of this material was also decreased, similar to the periodate and Endo-H-treated rt-PA. Conversely, when rt-PA was produced in the CHO 15B cell line, which can produce only high mannose oligosaccharide structures on glycoproteins, the clearance was increased by a factor of 1.8. These results demonstrate that the removal of rt-PA from the blood depends significantly upon the nature of its oligosaccharide structures.
The Anticoagulant Properties of a Modified Form of Protein S
Authors: Mitchell C A , Kelemen S M , Salem H H 
Published: June 2018

SummaryProtein S (PS) is a vitamin K-dependent anticoagulant that acts as a cofactor to activated protein C (APC). To date PS has not been shown to possess anticoagulant activity in the absence of APC.In this study, we have developed monoclonal antibody to protein S and used to purify the protein to homogeneity from plasma. Affinity purified protein S (PSM), although identical to the conventionally purified protein as judged by SDS-PAGE, had significant anticoagulant activity in the absence of APC when measured in a factor Xa recalcification time. Using SDS-PAGE we have demonstrated that prothrombin cleavage by factor X awas inhibited in the presence of PSM. Kinetic analysis of the reaction revealed that PSM competitively inhibited factor X amediated cleavage of prothrombin. PS preincubated with the monoclonal antibody, acquired similar anticoagulant properties. These results suggest that the interaction of the monoclonal antibody with PS results in an alteration in the protein exposing sites that mediate the observed anticoagulant effect. Support that the protein was altered was derived from the observation that PSM was eight fold more sensitive to cleavage by thrombin and human neutrophil elastase than conventionally purified protein S.These observations suggest that PS can be modified in vitro to a protein with APC-independent anticoagulant activity and raise the possibility that a similar alteration could occur in vivo through the binding protein S to a cellular or plasma protein.
Antithrombin III Geneva: A Hereditary Abnormal AT III with Defective Heparin Cofactor Activity
Authors: de Moerloose P A , Reber G , Vernet Ph , Minazio Ph , Bouvier C A 
Published: June 2018

SummaryA 43-year-old man presented a pulmonary embolism. The unusual circumstances of apparition, the age and the increased heparin requirements suggested an antithrombin III (AT III) deficiency. AT III activity was low in the propositus and seven other members of his family (mean 55%), but immunologic levels were normal (mean 110%). Crossed immunoelectrophoresis in absence of heparin showed a normal pattern, but in presence of heparin showed an abnormal peak as compared with controls. Kinetics experiments showed a normal inhibition of thrombin and Xa in absence of heparin, but abnormal in presence of heparin. Affinity chromatography on heparin-Sepharose revealed two populations of AT III, one of which was devoid of heparin cofactor activity. The toponym AT III Geneva is proposed for this new familial abnormal AT III with defective heparin cofactor activity.
The Interaction of Activated Protein C and Thrombin with the Plasminogen Activator Inhibitor Released from Human Endothelial Cells
Authors: de Fouw N J , van Hinsbergh V W M , de Jong Y F , Haverkate F , Bertina R M 
Published: June 2018

SummaryThe effects of human activated protein C (APC) and thrombin on plasminogen activator inhibitor (PAI-1) released from cultured human umbilical endothelial cells, grown in serum-free 35S-methionine containing medium, were studied in two ways: 1) measurement of PAI-1 activity with an amidolytic assay, and 2) immunoprécipitation of the medium with anti-PAI-1 IgG, antiprotein C IgG or anti-thrombin IgG followed by SDS-PAGE and autoradiography.Addition of APC or thrombin to the endothelial cell conditioned medium results in a time and concentration dependent loss of PAI-1 activity and in the degradation of PAI-1 from 46 kD into a 42 kD product.After incubation of the medium with APC in the presence of cells, an additional band of 95 kD was found, which could be immunoprecipitated with both anti-PAI-1 IgG and anti-protein C IgG, indicating the formation of an APC-PAI-1 complex before degradation occurs. No complex could be detected after incubation of the medium with thrombin in the presence of endothelial cells.Blocking the active sites of APC and thrombin prevented both the formation of APC-PAI-1 complexes and the inactivation and degradation of PAI-1. After removal of the active PAI-1 from the medium, no degradation of the inactive PAI-1 by APC or thrombin could be found.It is concluded that both APC and thrombin react with the active PAI-1, resulting in inactivation and degradation of PAI-1.
Evaluation of Monoclonal Antibodies to vWf Antigen for Use in Autoradiographing vWf Multimer Analysis
Authors: Enayat M S , Hill F G H , Robinson W , Prowse C V , Hornsey V S 
Published: June 2018

SummaryNine monoclonal antibodies (MAb, coded ESvWF 1-5, 7-10) to human von Willebrand’s factor (vWf) have been studied for their labelling characteristics with 125I and their ability to demonstrate vWf multimers by autoradiography after discontinuous SDS electrophoresis on agarose and agarose/acrylamide gels in plasma from normal and von Willebrand’s disease (vWD) patients. Of ESvWF 1, 2, 4, 7, 8 and 9, ESvWF 2 gave autoradiographs most similar to those obtained with a polyclonal antibody. The others gave much fainter staining of all bands suggesting that the epitope detected by ESvWF 2 is either more common or, less easily altered by SDS than the epitopes identified by the other MAb’s. ESvWF 2 gave a different staining pattern with a IIC vWD patient than that obtained using a polyclonal antibody. The most striking result, however, was shown by ESvWF 3, 5 and 10 which failed to stain the lower band of the lower molecular weight multimer. This suggests that the lower triplet band, unlike the central and upper bands of the triplet, does not contain the epitope identified by these three MAb’s. With these reagents it has been possible to show, for the first time, that epitope differences do exist between the constituent bands of the vWf triplet.
Responses of Platelets to Strains of Streptococcus sanguis: Findings in Healthy Subjects, Bernard-Soulier, Glanzmann’s, and Collagen-Unresponsive Patients
Authors: Soberay A H , Herzberg M C , Rudney J D , Nieuwenhuis H K , Sixma J J , Seligsohn U 
Published: June 2018

SummaryThe ability of endocarditis and dental strains of Streptococcus sanguis to induce platelet aggregation in plasma (PRP) from normal subjects were examined and compared to responses of PRP with known platelet membrane glycoprotein (GP) and response defects.
S. sanguis strains differed in their ability to induce normal PRPs to aggregate. Strains that induced PRP aggregation in more than 60% of donors were significantly faster agonists (mean lag times to onset of aggregation less than 6 min) than those strains inducing response in PRPs of fewer than 60% of donors.Platelets from patients with Bernard-Soulier syndrome aggregated in response to strains of S. sanguis. In contrast, platelets from patients with Glanzmann’s thrombasthenia and from a patient with a specific defect in response to collagen were unresponsive to S. sanguis. These observations show that GPIb and V are not essential, but GPIIb-IIIa and GPIa are important in the platelet response mechanism to S. sanguis. Indeed, the data suggests that the platelet interaction mechanisms of S. sanguis and collagen may be similar.
Eine In-Vitro-Methode zur Bestimmung der Thrombozytenadhäsivität
Authors: Jacobi E , Hagemann G , Poliwoda H 
Published: June 2018

ZusammenfassungEs wird über eine neue In-vitro-Methode zur Bestimmung der Thrombozyten-adhäsivität berichtet. Aus strömendem Zitratblut scheiden sich an Kunstfasern Plättchen ab, deren Menge mit Hilfe des Folin-Reagenz bestimmt wird. Dabei müssen folgende Parameter konstant gehalten werden: Blutströmungsgeschwindigkeit, Temperatur und Tageszeit der Blutabnahme. Als besonders vorteilhaft haben sich Fasern mit rauher Oberfläche erwiesen. Die Adhäsivität als Funktion der Thrombozytendichte (n) stellt sich in nächster Annäherung als 0,1 √n heraus, welches eine Umrechnung auf eine normale Thrombozytendichte bei unterschiedlich gemessenen Dichten erlaubt. Die Standardabweichung der Meßwerte wurde mit ± 9,1%, der Meßbereichsumfang mit wenigstens dem 30fachen der Standardabweichung bestimmt.
Appearance of Thrombogenic Tendency Induced by Adrenaline and Its Prevention by β-Adrenergic Blocking Agent, Nialamide and Pyridinolcarbamate
Authors: Yamazaki H , Sano T , Odakura T , Takeuchi K , Matsumura T , Hosaki S , Shimamoto T 
Published: June 2018

SummaryIn 52 men and 33 women, the total, adhesive and nonadhesive platelet counts, onestage prothrombin time, euglobulinlysis time, and plasma nonesterified fatty acid were measured before and after an intravenous injection with 0.1 μg/kg of adrenaline or 1-noradrenaline. Three hours before the injection, placebo, 30 mg of phenoxybenzamine, 300 mg of pronethalol, 100 mg of nialamide or 100 mg of pyridinolcarbamate was administered orally under the double blind technique. Five minutes after the injection with adrenaline in 15 cases pretreated with placebo, a decrease in adhesive platelet count, and a shortening of one-stage prothrombin time and euglobulin lysis time were observed with statistical significance (P ˂ 0.01 ∼ 0.05). These changes were not observed in 15 cases injected with saline or noradrenaline. The changes were not observed in 10 cases pretreated with pronethalol, but were observed in 10 cases pretreated with phenoxybenzamine. So the effect of adrenaline may be due to stimulation of ß-adrenergic receptor sites. Meanwhile, the decrease in adhesive platelet count and the enhancement of blood coagulability were prevented by nialamide and pyridinolcarbamate, while the enhancement of fibrinolysis was not. The preventive effect of nialamide was less than that of pyridinolcarbamate. Phenoxybenzamine and nialamide prevented an increase in systolic blood pressure induced by adrenaline, and pronethalol prevented tachycardia by adrenaline, while pyridinolcarbamate did not affect these changes. Changes in plasma nonesterified fatty acid showed no relationship to the above hematological changes.
The Effect of Stress and Warfarin on the Adrenal Gland in Relation to Spontaneous Hemorrhage, as Judged by Measurement of Adrenal Ascorbic Acid and Serum Corticosterone
Authors: Chattopadhyay S , Johnson D. D , Millar G. J , Jaques L. B 
Published: June 2018

SummaryRats were subjected to the following procedures: No treatment, Stressor (10% NaCl i.p.), Warfarin for 7 days, Stressor followed by Warfarin; and groups were sacrificed at intervals for assessment of spontaneous hemorrhage and of adrenal ascorbic acid concentration. There was no hemorrhage in the no treatment and stressor groups; some hemorrhage in the warfarin group; profound hemorrhage with Warfarin + Stressor. The adrenal ascorbic acid concentration was found to be lower, 8 h and again 5 days after stress, and remained lower in the warfarin + stress animals. Warfarin had no effect on adrenal ascorbic acid level.In another series of experiments in which the stress consisted of an electric current to the cage floor for 6 sec over 15 min, rats were sacrificed daily for determination of serum corticosterone concentration and occurrence of spontaneous hemorrhage. There was a statistically significant increase of serum corticosterone concentration with stress, warfarin and combined warfarin and stress treatments (P< 0.001 for all three variables). There was a significant correlation (r = 0.96 and 0.89, P< 0.01) for serum corticosterone concentration with hemorrhage score and incidence of hemorrhage in stressed rats receiving warfarin, but not in those receiving only warfarin. The results indicate an activation, rather than an exhaustion, of the pituitary-adrenal axis during the combined action of anticoagulant and stress, which results in the development of spontaneous hemorrhage.
Quantitative Determination of Intravascular Coagulation in Vivo in Various Organs in the Dog
Authors: Busch Ch , Lundqvist H , Saldeen T 
Published: June 2018

SummaryA technique for determination of intravascular coagulation in different organs by means of continuous external detection of 125I-fibrinogen in the dog is described.It is suggested that this technique would be of value in human beings as a complement to the present, often unsatisfactory methods for determination of microembolism.
The Estimation of Blood Platelet Survival
Authors: Murphy E. A 
Published: June 2018

SummaryA study has been made of the distortion introduced by using the multiple-hit (gamma) model for the construction of population curves where some of the underlying assumptions are violated. The three violations, over which, because of physiological evidence, there is greatest occasion for concern, are considered in some detail. These distortions are that a latent interval exists between hits so that true survival would follow a gamma distribution shifted to the right; that the probability of responding to an environmental insult may change with the age of the platelet so that survival would follow an Erlangian distribution; and that platelet destruction may be governed by competing processes of differing relative importances. Under fairly general conditions, the discrepancies between these models (if true) and the “best fit” (minimax) gamma function of integral order are small (less than 3%) especially when compared with the kind of experimental errors usually encountered.It seems then that until such time as very precisely measured data are available, the multiple-hit model may be used with confidence at least as a device for estimating the mean.It is pointed out, however, that the estimation of the number of hits to destruction, or the mean waiting time between them separately, is likely to be imprecise. Nevertheless, the estimation of the mean (which is the ratio of the number of hits to the reciprocal of the waiting time) may still be much more satisfactory than estimates not explicity defended by rational models. The latter consideration is statistical and will be dealt with in a later paper in this series.
The Leukocyte Digestion of Fibrinogen Degradation Products (FDP)
Authors: Gibiński K , Lipiński B , Trusz-Gluza M 
Published: June 2018

SummaryWhile the native fibrinogen is not digested by the leucocyte proteases both the early and late FDP are digestible without any denaturating reagent. Thus, this reaction may occur in vivo indicating an unknown role of granulocytes in paracoagulation.
A Comparative Study of Adult and Fetal Sheep Fibrinogen, Sulf-Fibrinogen and Fibrinogen Degradation Products
Authors: Loly W , Israels L. G , Bishop A. J , Israels E. D 
Published: June 2018

SummaryThe results of these comparative studies of adult and fetal sheep fibrinogen are as follows:1. Adult D fragments and sulf-fibrinogen are identical to their fetal counterparts when examined by acid alkaline polyacrylamide gel electrophoresis.2. Adult and fetal E fragments show identical mobility on acid and alkaline polyacrylamide gel electrophoresis, but in the alkaline system the adult E piece consistently shows 3 separate bands while the fetal E peice, with one exception, is one diffuse band. The pattern of banding of the two E fragments is identical in the acid gel system.3. Adult D and E fragments and sulf-fibrinogen are immunologically identical to their fetal counterparts.4. Thrombin times on fetal plasmas are, on the average, prolonged over those on adult plasmas ; this is probably due to the lower absolute fibrinogen concentration of fetal plasma.5. Adult and fetal fibrinogen showed no differences in the pH dependency of their thrombin times, indicating that the polymerization process is probably the same in both.6. It is essential, in studies of fibrinogen structure and function, to work with very pure fibrinogen preparations, free from fibrin monomers and fibrinogen degradation products.
Corrective Effect of Sialic Acid on the Clotting of Factor VIII Deficient Blood
Authors: Rubin H , Fernbach T , Ritz N. D 
Published: June 2018

SummaryOptimal concentrations of N-acetyl neuramic acid (NANA) accelerated the clotting of factor VIII deficient whole blood and plasma. There was no effect on normal plasma and certain other factor deficient plasmas.NANA increased thromboplastin formation by factor VIII deficient plasma, as measured by the Thromboplastin Generation Test.NANA possesses an inhibitory effect on rabbit brain thromboplastin and cephalin in recalcification tests, over the values of its controls, but-in sharp contrast, enhanced the effect of Russell Viper Venom (RVV) and RVV-cephalin.The amino sugar N-acetyl mannosamine, possessing common functional groups with NANA, also shortened the clotting time of factor VIII deficient whole blood and plasma.It is suggested that NANA acts as a cofactor to factor VIII which is present in trace amounts in hemophilic plasma.
The Adsorption of Coagulation Factors onto Phospholipids
Authors: Hemker H. C , Kahn M. J. P , Devilee P. P 
Published: June 2018

SummaryIt is shown that factors VIII and IX react with phospholipid in a way fully analogous to the reaction of factors V and X. From this it is concluded that a complex of factors VIII and IX adsorbed onto a phospholipid micelle may be the entity that activates factor X in the intrinsic pathway. The implications of this finding for the concepts of the reaction mechanism of blood coagulation are discussed. It is shown that instead of the original 7-step cascade of Macfarlane, a 4-step cascade consisting partly of complex enzymes is more probable.
Assay of Progressive Antithrombin in Plasma
Authors: Abildgaard U , Gravem K , Godal H. C 
Published: June 2018

SummaryA simple two-stage assay of progressive antithrombin activity in plasma is described. After heat defibrination, plasma is diluted VlO in buffer (pH 8.0) and incubated with thrombin for 3 min at 37° C. After incubation, residual thrombin activity is determined with standard substrate (antithrombin clotting time). By substituting buffer for diluted plasma, the buffer clotting time is determined. The antithrombin activity may be calculated from these two clotting times or read from a standard curve. It is expressed in per cent of pooled normal plasma. The range in 36 normal plasmas was 74-116%, the S. D. 11%, and the S. E. M. 5.7%. The combination of simplicity and accuracy makes the present method compare favourably with earlier methods.
A Simple Technique for the Measurement of Plasma Heparin Concentration during Anticoagulant Therapy
Authors: Marder V.J 
Published: June 2018

SummaryBlood is incoagulable for several hours after therapeutic doses of intravenous heparin when tested by the glass clotting time (CT) or activated partialthromboplastin test (APTT). A simple modification of the APTT is described which allows the quantitative measurement of plasma heparin levels at any time during therapy. In principal the test plasma is diluted in normal plasma before assay, thereby reducing the heparin concentration to a range which can be measured by the APTT. The corresponding plasma heparin concentration is estimated by reference to a single standard curve which applies for concentrationsfrom 0.1 to 10 I.U./ml of plasma. Since all samples are diluted in normal plasma, storage of blood at 4° or even 37° for up to 48 h does not significantly alter the results. The assay is applied in the study of plasma heparin disappearance time and in the control of anticoagulant therapy forthromboembolic disease.