bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Platelet of the Newborn Infant 5-hydroxytryptamine Uptake and Release
Authors: Whaun June M. 
Published: June 2018

SummaryIt is well recognized that some newborn infants experience unexplainable bruising, petechiae, and occasionally, intraventricular hemorrhage.Total endogenous 5-hydroxytryptamine (5-HT) and 14C-5-HT uptake and release Aver e studied as part of a comprehensive survey.Total endogenous 5-HT levels were assayed in platelets of normal adult subjects, parturient mothers, and full-term normal newborn infants. Mean values expressed as micromoles per 1011 platelets were 0.186 ±0.018 (S.E.), 0.138 ±0.02, and 0.069 ± 0.008 respectively. Mean values expressed as nanomoles per milligram platelet protein were 0.417±0.03 (S.E.), 0.371 ±0.04, 0.161 ±0.02, respectively. No significant difference was noted between samples from adult controls and those from mothers. Newborn platelets were significantly different from either adult control platelets or maternal platelets.
14C-5-HT binding was measured in platelet-rich plasma (PRP) in the three groups. No significant difference between the three groups was noted. 14C-5-HT release following addition of solubilized collagen to PRP was measured in each of the three groups. No significant difference was noted in samples from adult normal controls (mean value 53.2 ±2.5%) and samples from mothers who had not ingested aspirin or other drugs (mean value 53.7 ±3.4%). Newborn platelet samples in contrast did not release as completely as platelet samples of the other two groups (mean value 37.2±2.4%).Newborn platelets have both low serotonin stores, which may reflect immaturity of intestinal secretory function or block in amine synthesis, and an intrinsically defective reíase reaction which may reflect immaturity of membrane structure. Both these findings may provide further insight into altered hemostasis in the newborn.
Generalized Shwartzman Reaction Induced by Liquoid in the Rat
Authors: Evensen Stein A. , Shepro David 
Published: June 2018

SummaryIn an autoradiographic study the number of DNA-synthesizing aortic endothelial cells was compared 48 hours after an intravenous injection of the acidic polymer Liquoid or saline in rats. Doses of 1.5-2 mg per 100 g body weight produced a 14-fold increase in DNA-synthesizing endothelial cells and the generalized Shwartzman reaction. These results show that Liquoid causes severe endothelial injury.
Volume Distribution and Ultrastructure of Platelets in Acute Hog Cholera
Authors: Weiss E , Teredesai A , Hoffmann R , Hoffmann-Fezer G 
Published: June 2018

SummaryHog cholera is an excellent model to study virus related haemorrhagic diatheses of man, since coagulation parameters and morphology of swine platelets are quite similar to those of man. 15 pigs were infected with hog cholera virus. The volume distribution curves of platelets, immediately stabilized with glutaraldehyde after sampling, indicates a right shift of their peaks after infection, which is due to increase in number of megathrombocytes and aggregates. Electron microscopy shows from the first day p.i. an increase in number of giant platelets, and thrombocytes with multiple dense granules including “bull’s eyes”, more mitochondria, endoplasmic reticulum and Golgi apparatus. These findings indicate an accelerated thrombocytopoiesis, in which more immature platelets appear in the blood stream. The other changes (dilatation of surface connecting system, increase of dense tubular system and microtubuli, formation of aggregates) are obviously due to a release-reaction, following adsorption and phagocytosis of the virus by the platelets. The studies reveal that in the beginning of acute hog cholera platelets already are directly damaged by the virus. Since thrombocytopoiesis cannot match the severe and progredient destruction of platelets, from the second day p.i. marked thrombocytopenia develops. Together with virus-induced endothelial lesions and disseminated intravascular coagulation, as described by us, it causes the haemorrhagic diathesis, typical for terminal stages of acute hog cholera.
The Effect of Some Synthetic Arginyl and Lysyl Compounds on Clotting and Fibrinolysis
Authors: Weinstein M. J , Doolittle R. F 
Published: June 2018

SummaryThe effects of a number of synthetic arginyl- and lysyl-compounds on clotting and fibrinolysis have been studied. The lysyl derivatives had no significant effect on the clotting of recalcified plasma or recalcified euglobulin preparations, but tosyllysine (TL) and tosyllysine methyl ester (TLME) were very effective inhibitors of fibrinolysis. Certain arginyl-peptides (in particular, tosylarginylsarcosine methyl ester) were very effective at delaying clotting in these systems. These same substances gave rise to an exaggerated thrombin production, however, evidently by interfering with the natural thrombin activation of plasma antithrombin(s).
Induction of Disseminated Intravascular Coagulation in the Factor XII-deficient Fowl
Authors: Skjørten Fredrik , Evensen Stein A. 
Published: June 2018

SummaryBirds are naturally deficient in the coagulation factors responsible for the contact activation reactions in mammalian plasma. In the present study, fowl lungs were examined for evidence of disseminated intravascular coagulation (DIC) 5 min or 4 hours after injection of either Liquoid or bacterial endotoxin. These substances are potent initiators of DIC in mammals, and activation of factor XII is believed to be essential for their triggering effect.Liquoid injection produced intravascular deposits with the light microscopical staining properties of fibrin. However these deposits had a purely granular ultra-structure; their formation was not prevented by adequate anticoagulation, and there was no concomitant thrombocyte aggregation. It is suggested that the deposits represent precipitates of plasma proteins, including fibrinogen.Endotoxin failed to produce clinical reactions, intravascular deposits or thrombocyte aggregates. In contrast, animals injected with homologous tissue thromboplastin died, and fibrillar material with the ultrastructural appearance of fibrin, as well as thrombocyte aggregates were found in small pulmonary vessels. These effects were completely prevented by anticoagulation.We conclude that both Liquoid and endotoxin failed to trigger DIC in the factor XII-deficient fowl, suggesting that these substances depend on the contact activation reactions for the generation of thrombin.
Leucocytes and Thrombosis
Authors: Banks D.C , Mitchell J.R.A 
Published: June 2018

SummaryThe rate of white cell loss from heparinised whole blood in a rotating glass flask has been used to study leucocyte behaviour.Leucocyte loss requires divalent cations and magnesium is more active than calcium. Sulphydryl blockers and potassium cyanide inhibit white cell loss, showing that sulphydryl groups and a glycolytic pathway play a part in leucocyte adhesion.White cell loss from plasma rotated in a flask is negligible, but is markedly increased by adding red cells, red cell sonicates or ADP.The role of platelets and of substances which affect platelet behaviour in white cell adhesion is discussed.
A Preliminary Study on the Acetylcholinesterase and Butyrylcholinesterase of Human Platelets
Authors: Chuang Hanson Y.K. , Mason Reginald G. 
Published: June 2018

SummaryEvidence obtained from a colorimetrie assay method and from a more sensitive and specific radiometric assay method strongly suggests that one of the cholinestera-ses of intact human platelets is an acetylcholinesterase. Examination of disrupted platelets indicates that a butyrylcholinesterase also may be associated with these cells. However, it remains to be seen whether the butyrylcholinesterase is actually present within the platelets’ cytoplasm or whether it is a plasma enzyme trapped in the surface-connected canalicular system of these cells during the process of their isolation from blood.
Platelet Factor 3 Activity Made Available from Human Platelets by ADP
Authors: Gold Michael , Evensen Stein A. , Belamarich F.A , Shepro David 
Published: June 2018

SummaryPretreament of normal human platelets with colchicine at a final concentration of 10-3 M strikingly modifies their subsequent reaction to ADP. The generation of platelet factor 3 activity is inhibited, the secondary wave of aggregation fails to appear, and platelet factor 4 is not released. Colchicine also inhibits the increase in platelet factor 3 activity that results from washing and centrifugation of platelets.
Evaluation of a Semi-micro Method for Measuring Platelet Aggregation in Whole Blood Samples
Authors: Gordon John L. 
Published: June 2018

SummaryPlatelet aggregation has been measured rapidly and simply in 0.5 ml samples of citrated whole blood, by counting the unaggregated platelets remaining after the samples were mixed with aggregating agents, and the erythrocytes rapidly sedimented by adding physiological saline. Concentration-dependent aggregation responses were obtained with adenosine diphosphate, glass beads, serotonin and connective tissue. Aggregation induced by mixing alone was also measured.The aggregation responses were altered by minor changes in citrate concentration, and increased during the first hour after venepuncture. In heparinised blood samples, platelet counts were reduced and all aggregation responses substantially increased. Extending the time interval between aggregating stimulus and platelet counting had no significant effect on the aggregation responses. The main source of technical error was sampling for platelet counts, and the variablility was inversely related to the size of micropipette used. Results of tests in volunteers established the normal range of responses to aggregating agents, and showed that blood samples taken weeks apart from the same subject gave more variable responses than did samples taken an hour apart.
Metabolic Properties of Human Platelet Membranes
Authors: Kaulen Hermann Dietrich , Gross Rudolf 
Published: June 2018

SummaryThe preparation of human platelet membranes and their characterization by electron microscopy and their enzymatic, lipid and protein content is reported. The membranes can be prepared in good yield from about one unit of blood. Using both sucrose and Ficoll density gradients as controls to each other, constant and reproducible membrane preparations of comparable biochemical composition are obtained. Electron microscopy shows uniform membrane structures without other contaminating subcellular organelles. The membranes are characterized by the enrichment of the acid para-nitrophenylphosphatase, a low activity of granular enzymes and by proteins of molecular weights from 20.000 to more than 100.000. They show a high content of N-acetylneuraminic acid, cholesterol, phospholipids, and in particular a high percentage of sphingomyelin. This preparation can be used for metabolic tracer studies at a subcellular level.
Human Coumarin Prothrombin
Authors: Cesbron Nicole , Boyer Catherine , Guillin Marie-Claude , Ménaché Doris 
Published: June 2018

SummaryThe abnormal prothrombin produced in patients under coumarin treatment has been isolated from oxalated plasma. After removal of normal prothrombin by adsorption on to small amounts of barium sulfate, coumarin prothrombin proved to be adsorbable on to larger amounts of barium sulfate. After elution into citrate the coumarin prothrombin was precipitated with ethanol and chromatographed on DEAE cellulose. Using a similar linear gradient than for normal prothrombin, the coumarin prothrombin was eluted ahead of normal prothrombin. Immunological studies performed on chromatographed coumarin prothrombin showed that it shared with normal prothrombin the main antigenic determinants and a complete line of identity was obtained when tested against antihuman normal prothrombin antiserum. On crossed Immunoelectrophoresis the electrophoretic mobility of coumarin prothrombin, unlike normal prothrombin, was not modified by the addition of calcium ions. Coagulation studies revealed that coumarin prothrombin could not be activated by physiological activators whereas conversion to thrombin was possible by non physiological activators such as staphylocoagulase and Echis carinatus venom. The amounts of thrombin generated under staphylocoagulase activation per 100 antigen units were similar to those generated by normal prothrombin. The amounts of thrombin obtained under the action of the venom were less than from normal prothrombin. In addition, the activation of coumarin prothrombin proved to be slower than for normal prothrombin.
Further Evidence for a Humoral Control of Factor VIII Plasma Levels
Authors: Landaburu Ricardo H. , Castellanos Delicia E. 
Published: June 2018

SummaryFactor VIII increase after stress or adrenergic stimulation appears to be justified by ACTH release, which in turn liberates a principle other than steroids, from the adrenal cortex. A substance isolated from adrenal cortex and denominated S3 increase, when injected, the level of plasma factor VIII. The rise in factor VIII after S3 also occurs in adrenalectomized animals where ACTH or catecholamines administration gives negative results.
Effect of Aspirin on the Thrombelastogram of Human Blood
Authors: de Gaetano G , Vermylen J 
Published: June 2018

SummaryThrombelastograms of both native blood and re-calcified platelet-rich plasma samples taken from subjects given a single oral dose of aspirin (1 gram) were not significantly different from the pretreatment recordings. Aspirin also did not modify the thrombelastogram when preincubated in vitro with platelet-rich plasma at concentrations inhibiting the platelet “release reaction” by collagen. Thrombelastography therefore cannot evaluate the effect of aspirin on platelet function.
Leucocytes and Thrombosis
Authors: Banks D. C , Mitchell J. R. A 
Published: June 2018

SummaryNormal white cell adhesiveness was found in a group of patients with idiopathic thrombocytopenia in whom the mean platelet count was 34,000 per cu. mm.Marked elevation of white cell adhesiveness was observed after splenectomy. This did not correlate with changes in the white cell count but did parallel the increase in platelet count and adhesiveness.White cell adhesiveness was increased in patients with a recent myocardial infarction. As it was also increased in patients with other acute illnesses and was normal in patients with old myocardial infarcts, the test is not of diagnostic value in thrombotic disease.
A Comparison of the Effects of Antihistamines on Platelet Function
Authors: Thomson Carl , Forbes Charles D. , Prentice C. R. M 
Published: June 2018

SummaryAntihistamines are frequently given to haemophilic patients prior to replacement therapy. As these compounds have inhibitory properties against platelets, the relative effects of three commonly used antihistamines against platelets were compared. The actions of promethazine, chlorpheniramine, or mepyramine were tested against platelet aggregation induced by A.D.P., collagen, noradrenaline, and 5 hydro-xytryptamine, as well as platelet adhesiveness and the in vivo rat tail bleeding time. Overall, promethazine had the greatest inhibitory effects, mepyramine had intermediate, and chlorpheniramine least effect. It is suggested that these findings may be important when antihistamines are given to patients with intrinsic coagulation defects and that the compounds which possess the greatest inhibitory action against platelets should be avoided.
Platelets and Clot Retraction
Authors: Bottecchia Domenico , Fantin Gianpaolo 
Published: June 2018

SummaryThe effect of Ca2+, Mg2+, Mn2+ and some drugs known to influence smooth muscle behaviour on human and rat whole blood and PRP clot retraction was studied.The force of the retraction was measured by a dynographic apparatus using electrical transduction. Clot retraction was studied by thrombelastographic method as well.The results obtained by using EDTA and EGT A show that both Ca2+ and Mg2+ are necessary for the normal development of clot retraction. They suggest the coexistence in the platelets of an accessible calcium fraction and a fraction not readily accessible to chelating agents, which is released following the calcium chelation in the first fraction.MnCl2 inhibits clot retraction and induced a quick, complete and irreversible relaxation of fully contracted clots. It is concluded that there are some analogies between blood clots and smooth muscle.The absence of any effect of adrenaline, noradrenaline and ADP, which strongly modify smooth muscle contraction, is not surprising. This is probably because clotting caused by thrombin-triggered platelets has already produced a maximal clot retraction.
Differentiation between Plasminogen Activators by Means of Epsilon- Aminocaproic Acid
Authors: Kok P , Astrup T 
Published: June 2018

SummaryThe differentiation between plasminogen activators from tissue and urine by means of the patterns of inhibition produced by epsilon-aminocaproic acid (EACA) in fibrin plate assays was investigated. Different inhibition patterns reflected genuine differences between two types of activators. The method allows the differentiation between two types of activators in weakly fibrinolytic and impure activator solutions.A biphasic pattern of inhibition by EACA was observed with human urine as well as with the purified urokinase preparations. The degree of enhancement of fibrinolysis observed in the millimolar concentration range of EACA fluctuated with the fibrin substrate and was, in part, related to its plasminogen content. Increasing concentrations of EACA produced a uniformly increasing inhibition of preparations of tissue activator obtained in various degrees of purity from porcine ovary and heart. Plasmin was uniformly inhibited by EACA. Inhibition of plasmin required about 100 times higher concentrations of EACA than inhibition of tissue activator-induced fibrinolysis. EACA produced a slightly biphasic pattern of inhibition with plasminogen activator from human uterine tissue.
Evidence of Phylogenetic Canalisation of the Circulating Platelet Mass in Man
Authors: von Behrens W. E 
Published: June 2018

SummaryPhylogenetically mammalian platelets are an apocrine secretion from nucleated thrombocytes, and biologically the number of circulating fragments is irrelevant compared with their total mass and biochemical function. The literature on human genetic derangements affecting the circulating platelet mass is reviewed. The product of platelet count and platelet volume is shown to be “canalised” since many congenital forms of thrombocytopenia are associated with a reciprocal increase in the mean platelet volume. Considerations of platelet size are essential since macrothrombocytopenia is a racial characteristic of many Mediterranean peoples and probably also occurs frequently in others races. The location of platelet disorders in relation to the phylogenetic canal provides an objective classification which has diagnostic, therapeutic and prognostic significance.
Reaction Characteristics of Antiprothrombin Antibody on the Activation of Prothrombin (Sheep)
Authors: Hussain Q. Z , Chaudhuri S 
Published: June 2018

Summary1. Prothrombin was purified by a series of steps and subsequently on DEAE-Cellu- lose chromatography and specific antibody to pure prothrombin was prepared.2. The effect of Anti-prothrombin antibody was tested on the activation of prothrombin. The generated thrombin was assayed for its clotting function as well as for esterase activity on TAMe (Tosyl-Arginine-Methyl ester) as substrate.3. Anti-prothrombin antibody inhibits the clotting function of generated thrombin completely but its esterase function is only partially affected.
Separation of Sub-Units of Antihemophilic Factor (AHF) by Agarose Gel Chromatography
Authors: Weiss H. J , Phillips Louise L. , Rosner W. 
Published: June 2018

SummaryThe molecular weight of antihemophilic factor (AHF) in plasma and cryoprecipitate was studied by chromatography on agarose gel (Bio-Gel A, 1.5 M). At a pH of 7.4 and the ionic strength of plasma, AHF appeared in the void volume as a sharp, symmetrical peak, indicating a molecular weight of 1.5 million or greater. Similar findings were obtained in a patient with congenital afibrinogenemia. At a pH of 7.7, the major peak of AHF-activity was again found in the void volume, but a spreading of activity into higher elution volumes was also observed. In 1 M NaCl, pH 7.4, AHF dissociated into active sub-units of varying molecular size. The molecular weights of the smallest subunits were estimated to be 169,000-194,000. These studies provide further evidence that AHF is a high molecular weight substance, not associated with fibrinogen, whose quarternary structure may be disrupted to produce active sub-units of varying sizes.
Platelet Metabolism during the Interiorization of Two Different Types of Particulate Matter
Authors: Cooper I. A. , Cochrane P , Firkin B. G. , Pinkard K. J. 
Published: June 2018

SummaryIt has been suggested that human platelets possess the ability to phagocytose particulate matter similar to the polymorphonuclear leukocyte. However some difference of opinion has arisen regarding this contention, particularly as differences have been demonstrated with regard to the observed metabolic changes occurring in platelets related to such a process.The experiments reported in this paper were designed to observe the aerobic and anaerobic metabolism in human platelets during and following interiorization of two different particles, viz. polystyrene latex and thorotrast. The results of these experiments show a marked difference between both types of particles with regard to observable metabolic changes despite the rapid interiorization of both types of material. Some alteration occurs in both aerobic and anaerobic metabolism a considerable time after interiorization of latex, whereas no alteration could be demonstrated after interiorization of thorotrast. It is suggested that the interiorization of particulate matter is by some process other than phagocytosis and that observed metabolic changes related to latex may be due to a release reaction.
On the Early Detection of Intravascular Coagulation
Authors: Fedder G , Prakke Elisabeth M. , Vreeken J 
Published: June 2018

SummarySince the conception of intravascular coagulation has been introduced in clinical medicine, the interest of clinicians in the early detection of this syndrome is continuously increasing. Therefore small amounts of thrombin and thromboplastin were infused into rabbits and special parameters, such as presence of an activated form of factor V and occurrence of a positive fibrin monomer test, were checked. As it turned out, activation of factor V (proaccelerin, accelerator globulin or AcG) was an earlier sign of intravascular coagulation than the appearance of a positive gelation test, which may occur without changes in fibrinogen or the number of blood platelets. These experiments could be of value for the early detection of intravascular coagulation in man.
Thrombocytopenia Caused by Antigen-Antibody Reactions with Special Reference to Intravascular Coagulation
Authors: Fedder G , Prakke Elisabeth M. , Vreeken J 
Published: June 2018

SummarySoluble antigen-antibody complexes were infused in a group of non-immunized rabbits. Furthermore, antigen solutions were infused or injected into a group of rabbits, immunized with the corresponding antigen. In both groups a profound fall in the number of blood platelets was demonstrated. However, increased or decreased factor V activity was not seen in any of the rabbits; changes in the level of fibrinogen did not occur, and circulating fibrin monomers as a sign of thrombinemia could not be found.The mechanism by which immunologieally induced thrombocytopenia can lead to diffuse intravascular coagulation is briefly discussed.