bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of the Platelet Response to Laser- induced Microvascular Injury
Authors: McKenzie F. N , Arfors K.-E , Matheson N. A 
Published: June 2018

SummaryA study has been made of the biochemical factors underlying the platelet response to laser-induced microvascular injury. A platelet aggregating substance is produced at sites of laser-induced injury which markedly stimulates platelet activity at a site of injury inflicted a short distance downstream. Distal sites of injury are not similarly influenced if the distance between the injuries is increased or if the proximal site no longer shows platelet-stimulating activity. The stimulating effect of an adjacent proximal injury on platelet activity at a distal site is inhibited by local intra-arterial infusion of adenosine. Measurements of arterial blood pressure and microvascular blood flow velocity during adenosine infusion showed that its inhibitory effect on platelet activity is largely independent of its vasodilator properties. The effect of infusion of different adenosine phosphates (AMP, ADP, ATP) was also studied. Very small amounts of ADP markedly stimulated platelet activity and the emboli formed were similar to those normally produced at sites of laser injury. At high concentration AMP inhibited while ATP stimulated platelet activity in vivo. The results emphasise the fundamental role of ADP as a mediator of the platelet response at sites of laser- induced microvascular injury.
Effects of Vitamin E Administration on Platelet Function and Serum Lipid Peroxides in DOCA-Salt Hypertensive Rats
Authors: Umegaki Keizo , Saegusa Hiromi , Kurokawa Masato , Ichikawa Tomio 
Published: July 2018

SummaryEffects of vitamin E on platelet function and serum lipid peroxide levels were investigated in DOCA-salt hypertensive rats. In the hypertensive rats, ADP- and collagen-induced platelet aggregation in whole blood were markedly attenuated and accompanied by a reduction of serotonin content as compared with the normotensive controls. These facts indicated the appearance of exhausted platelets, which have already been activated in vivo, due to the hypertension. Platelet vitamin E levels were decreased by 50%, while serum lipid peroxide levels were increased 3.6-fold in the hypertensive rats. Vitamin E administration (10 times the dietary intake) during the experimental periods did not influence either the aggregability or the serotonin content of platelets from the hypertensive rats. However, vitamin E administration significantly prevented the elevation of serum tipid peroxides due to the hypertension. These results suggest that vitamin E administration has little effect on platelet activation in vivo due to DOCA-salt hypertension.
Recombinant Tissue Factor as Substitute for Conventional Thromboplastin in the Prothrombin Time Test
Authors: Tripodi Armando , Arbini Arnaldo , Chantarangkul Veena , Mannucci Pier Mannuccio 
Published: July 2018

SummaryRelipidated recombinant tissue factor (r-TF) has been assessed in comparison with conventional rabbit brain thromboplastin (Manchester Reagent) for its suitability for measurement of prothrombin time (PT). The International Sensitivity Index (ISI) of r-TF calibrated against the International Reference Preparation BCT/253 (human plain) was found to be 0.96 and 1.12 with instrumental and manual techniques. Our study of plasmas from patients with congenital deficiencies of clotting factors covering a wide range of severity demonstrates that r-TF is able to detect even minor deficiencies of factors involved in the extrinsic and common coagulation pathways. Patients with liver diseases were correctly diagnosed with a prevalence of abnormal results comparable for both reagents. Between-assay reproducibility expressed as coefficient of variation was 2.3 % and 3.9 % at normal and abnormal PT levels.In conclusion, our evaluation shows that relipidated r-TF possesses the necessary requisites of sensitivity, diagnostic accuracy and reproducibility which make it a suitable candidate for PT determination both for monitoring oral anticoagulant therapy and diagnosing congenital and acquired clotting factor deficiencies. Moreover, being a highly defined reagent it may constitute a step forward in the standardization of PT testing.
Haplotype Analysis of Identical Factor IX Mutants Using PCR
Authors: Green Peter M , Montandon A Jane , Ljung Rolf , Nilsson lnga Marie , Giannelli Francesco 
Published: July 2018

SummaryWe have detected the mutations in the factor IX genes from all of the haemophilia B patients registered at Malmo haemophilia centre (45) and are currently examining the entire UK haemophilia B population. From these studies we have found 13 base substitutions which have recurred in 1-6 other, presumably unrelated, patients. In order to determine the minimum number of independent repeats of each mutation we have used PCR to examine the five factor IX polymorphisms forming the most informative combinations and we have characterised the haplotype of each patient. Patients with different haplotypes are assumed to be unrelated and thus to carry independent mutations. All but one of the 13 mutations occur in at least 2 haplotypes thus pinpointing 12 mutational hotspots and mutations that can be clearly considered detrimental. Two of the 13 substitutions occur at non-CpG sites.
Reaction of Acetaldehyde with Human Platelets
Authors: Spertini Olivier , Hauert Jacques , Bachmann Fedor 
Published: July 2018

SummaryPlatelet function defects observed in chronic alcoholics are not wholly explained by the inhibitory action of ethanol on platelet aggregation; they are not completely reproduced either in vivo by short-term ethanol perfusion into volunteers or in vitro by the addition of ethanol to platelet-rich plasma. As acetaldehyde (AcH) binds to many proteins and impairs cellular activities, we investigated the effect of this early degradation product of ethanol on platelets. AcH formed adducts with human platelets at neutral pH at 37° C which were stable to extensive washing, trichloracetic acid hydrolysis and heating at 100° C, and were not reduced by sodium borohydride. The amount of platelet adducts formed was a function of the incubation time and of the concentration of AcH in the reaction medium. At low AcH concentrations (<0.2 mM), platelet bound AcH was directly proportional to the concentration of AcH in the reaction medium. At higher concentrations (≥0.2 mM), AcH uptake by platelets tended to reach a plateau. The amount of adducts was also proportional to the number of exposures of platelets to pulses of 20 pM AcH.AcH adducts formation severely impaired platelet aggregation and shape change induced by ADP, collagen and thrombin. A positive correlation was established between platelet-bound AcH and inhibition of aggregation.SDS-PAGE analysis of AcH adducts at neutral pH demonstrated the binding of [14C]acetaldehyde to many platelet proteins. AcH adduct formation with membrane glycoproteins, cytoskeleton and enzymes might interfere with several steps of platelet activation and impair platelet aggregation.This in vitro study shows that AcH has a major inhibitory action on platelet aggregation and may account for the prolonged ex vivo inhibition of aggregation observed in chronic alcoholics even in the absence of alcoholemia.
Rapid Isolation of Human Endothelial Cells from Whole Blood Using S-Endo1 Monoclonal Antibody Coupled to Immuno-Magnetic Beads: Demonstration of Endothelial Injury after Angioplasty
Authors: George F , Brisson C , Poncelet P , Laurent J C , Massot O , Arnoux D , Ambrosi P , Klein-Soyer C , Cazenave J P , Sampol J 
Published: July 2018

SummaryThe presence in whole blood of circulating endothelial cells (EC) has been a subject of debate for many years. It could represent a good marker of vessel injury. We demonstrate here that human endothelial cells can be directly isolated and identified in circulating blood by means of an endothelial cell specific monoclonal antibody, S-Endol, coupled to micromagnetic beads. The specificity and efficacy of the assay were established using normal blood samples with cultured EC added. Specific rosettes formed between EC and beads could subsequently be isolated with a magnet. The rosetted cells were recovered with a yield >80%. Their endothelial origin was confirmed by the positive labelling of von Willebrand factor and thrombomodulin, as well as the presence of Weibel-Palade bodies. We applied this method to demonstrate significantly increased levels of EC in venous and arterial human blood samples in patients undergoing heart catheterization. This new whole blood immuno-separation method may be useful in determining endothelial cell injury in vascular disorders.
Processing and Characterization of Recombinant von Willebrand Factor Expressed in Different Cell Types Using a Vaccinia Virus Vector
Authors: Meulien P , Nishino M , Mazurier C , Dott K , Piétu G , Jorieux S , Pavirani A , Girma J P , Oufkir D , Courtney M , Meyer D 
Published: July 2018

SummaryThe cloning of the cDNA encoding von Willebrand factor (vWF) has revealed that it is synthesized as a large precursor (pre-pro-vWF) molecule and it is now clear that the prosequence or vWAgll is responsible for the intracellular multimerization of vWF. We have cloned the complete vWF cDNA and expressed it using a recombinant vaccinia virus as vector. We have characterized the structure and function of the recombinant vWF (rvWF) secreted from five different cell types: baby hamster kidney (BHK), Chinese hamster ovary (CHO), human fibroblasts (143B), mouse fibroblasts (L) and primary embryonic chicken cells. Forty-eight hours after infection, the quantity of vWF antigen found in the cell supernatant varied from 3 to 12 U/dl depending on the cell type. By SDS-agarose gel electrophoresis, the percentage of high molecular weight forms of vWF varied from 39 to 49% relative to normal plasma for BHK, CHO, 143B and chicken cells but was less than 10% for L cells. In all cell types, the two anodic subbands of each multimer were missing. The two cathodic subbands were easily detected only in BHK and L cells. By SDS-PAGE of reduced samples, pro-vWF was present in similar quantity to the fully processed vWF subunit in L cells, present in moderate amounts in BHK and CHO and in very low amounts in 143B and chicken cells. rvWF from all cells bound to collagen and to platelets in the presence of ristocetin, the latter showing a high correlation between binding efficiency and degree of multimerization. rvWF from all cells was also shown to bind to purified FVIII and in this case binding appeared to be independent of the degree of multimerization. We conclude that whereas vWF is naturally synthesized only by endothelial cells and megakaryocytes, it can be expressed in a biologically active form from various other cell types.
von Willebrand Factor in Plasma and Urine of Men with Premature Coronary Artery Disease
Authors: Silveira Angela M V , Elgue Graciela , Hamsten Anders , Blombäck Margareta 
Published: July 2018

SummaryPlasma and urine samples from 17 men who had suffered a myocardial infarction before the age of 45 years were quantitatively and qualitatively analyzed for von Willebrand factor antigen (vWF), and compared with samples obtained from controls. The levels of vWF in plasma and its characteristic multimeric composition in the patient samples were not different from those of the controls. However, when analyzed for lower molecular weight components, plasma samples from some patients contained more degraded material than those of the controls as indicated by the presence of an extra protein band of vWF related material having a molecular weight of about 200 kDa. The levels in urine of vWF and the molecular weight of the fragments excreted did not differ between patients and controls. A relative increase in excretion of lower molecular fragments was, however, observed in the patient group. In a second group of 97 consecutive post-infarction patients under the age of 45 years the extra 200 kDa vWF band was found in 46% of the patients, whereas it was not detected in control plasmas. Taken together these findings suggest that degraded forms of vWF occur in normal plasma and that a more extensive degradation may occur in patients with coronary atherosclerosis, which could account for the relative increase in the excretion of lower molecular weight fragments observed in these patients.
Sedimentation Behavior of Fibrinogen from Normal and Bleeder Swine
Authors: Cooper R. G , Cornell C. N , Muhrer M. E , Leimer K 
Published: June 2018

SummaryThe Missouri Bleeder Swine have prolonged bleeding time, low factor VIII levels, reduced platelet adhesion, and respond to plasma and serum transfusions in a manner similar to that of patients with von Willebrand’s disease. The swine disease is thus more similar to von Willebrand’s disease than to classical hemophilia. The present work demonstrates that the sedimentation behavior of fibrinogen from these bleeder swine is like that of normal swine and does not show the anomalous sedimentation pattern of fibrinogen from classical hemophiliacs.
The Estimation of Blood Platelet Survival
Authors: Murphy E. A , Francis M. E , Mustard J. F 
Published: June 2018

SummaryThe characteristics of experimental error in measurement of platelet radioactivity have been explored by blind replicate determinations on specimens taken on several days on each of three Walker hounds.Analysis suggests that it is not unreasonable to suppose that error for each sample is normally distributed ; and while there is evidence that the variance is heterogeneous, no systematic relationship has been discovered between the mean and the standard deviation of the determinations on individual samples. Thus, since it would be impracticable for investigators to do replicate determinations as a routine, no improvement over simple unweighted least squares estimation on untransformed data suggests itself.
Variants of Haemophilia B
Authors: Elödi Susan , Puskás Éva 
Published: June 2018

SummaryVariants of haemophilia B were examined by antibody-neutralization technique and by the ox brain thromboplastin time method. On the basis of the presence or absence of anomalous factor IX and of prothrombin time, four variants of haemophilia B were discerned. It is shown that the prolongation of prothrombin time, measured in our cases, cannot be attributed to an inhibitor in the patients’ plasma.
Cold Promoted Activation of Factor VII
Authors: Gjønnæss H 
Published: June 2018

SummaryThe activating principle (CPA) of the factor VII activation seen in plasmas of women taking oral contraceptives after overnight incubation of the plasmas at 0° C was investigated. The reaction was dependent on low temperature, and factor XII was indispensable. Concomitant with the activation of factor VII a 10–30 fold increase in TAME esterolytic activity was observed together with a near 100 per cent drop in plasma kininogen concentration. The results indicated that the activation of factor VII is linked to activation of the kallikrein system, and that the activator may be plasma kallikrein.
Tranexamic Acid in the Control of Spontaneous Bleeding in Severe Haemophilia
Authors: Rainsford S. G , Jouhar A. J , Hall Angela 
Published: June 2018

SummaryA double-blind cross-over study of the prophylactic value of tranexamic acid (“Cyklokapron”), in a dose of 3.0 g per day, against spontaneous bleeding episodes in severe haemophilia was undertaken. Records of bleeding episodes were maintained during therapy in twenty boys with confirmed clinical severity, over two school terms. A significant reduction (p <0.05) in spontaneous bleeding episodes was attained with an associated lessening in the transfusion requirement of therapeutic material, and without obvious side effects. Recommendations are made for further investigations.
On the Complex Formation of Antithrombin III with Thrombin
Authors: Binder B 
Published: June 2018

SummaryBased on gelfiltration studies, the part of AT III which becomes bound to thrombin during the process of in vitro blood coagulation was calculated to be about 40% of total AT III. Complexes consisting of one AT III and one thrombin molecule could not be detected while fractions corresponding to molecular weights of about 190,000 Dalton show AT III as well as thrombin activities. The AT III - thrombin complex in normal human serum consists, therefore, of either 2 AT III and 2 thrombin molecules or of one AT III and 4 thrombin molecules.
Behaviour of the Portal Clotting Time in Cats Following the Intraduodenal Administration of Heparin
Authors: Kokot Bogdan 
Published: June 2018

SummaryThis work makes an attempt to display the behaviour of portal clotting time after intraduodenal administration of heparin. The experiments were carried out in 20 cats, which were divided into two groups.In the first stage of investigation the normal clotting time was determined in portal vein and caudal vena cava. Afterwards the same parameters were investigated after intraduodenal administration of heparin or saline solution.It was shown that after intraduodenal administration of heparin the clotting time in portal vein in each case was prolongated, but in the caudal vena cava it remains normal. After intraduodenal administration of saline solution the clotting time in both portal vein and caudal vena cava was unchanged.
Conclusions. 1. In the performed experiments the heparin administered intraduodenally passes from the small intestine into the collection of the portal vein. 2. The lack of anticoagulative activity of the heparin given intraduodenally in the blood of the peripheral veins probably caused by a block present above the portal collection.
Role of Platelet Factor 3 in the Hypercoagulability Induced by Pregnancy and Oral Contraceptives
Authors: Renaud S , Gautheron P 
Published: June 2018

SummaryAs evaluated in a recording “coagulometer” the Stypven time of 16 to 19 days pregnant Holtzman rats was shorter than that of the controls solely in platelet-rich plasma but not in platelet-poor plasma collected in siliconized material when most of the platelets were removed by slow speed centrifugation (1000 G × 20 minutes). If the same blood was centrifuged at a higher speed (2000 G) the Stypven time was considerably shorter in the pregnant rats even if no platelets were left indicating that platelet factor 3 had been released in plasma during centrifugation.Identical results were obtained in 10 women taking oral contraceptives as compared to 10 controls. Depending on whether blood was collected in siliconized glassware or not, and final determination performed in plastic or glass, the cephalin clotting time of oral contraceptives treated women was found to be longer, equal or shorter than this of the controls. When it was shorter, a comparable reduction in the Stypven time indicated that the shortening was probably due to “release” of platelet factor 3 in the platelet-poor plasma, in the course of its preparation.
Inhibition by Phenol and Phenolic Acids of Platelet Release Reaction
Authors: Molinas Felisa C. 
Published: June 2018

SummaryIt has been postulated that the high phenol and phenolic acids plasmatic levels found in patients with chronic renal failure are contributory factors in the abnormal platelet function described in these patients. This hypothesis was corroborated by “in vitro” studies showing the deleterious effect of these compounds on certain platelet function after pre-incubation of PRP with phenol and phenolic compounds. The present studies were conducted to determine the influence of phenolic compounds on platelet release reaction. It was found that phenol inhibited from 62.5 to 100% the effect of the aggregating agents thrombin, adrenaline and ADP on platelet 5-HT-14C release. The phenolic acids p-, m-, and o-HPAA inhibited from 36.35 to 94.8% adrenaline and ADP-induced platelet 5-HT-14C release. Adrenaline-induced platelet ADP release was inhibited from 27.45 to 38.10% by the phenolic compounds. These findings confirm the hypothesis that phenolic compounds interfere with platelet function through the inhibition of the release reaction.
Trial of Aspirin and RA 233 in Prevention of Post-operative Deep Vein Thrombosis
Authors: Wood Edward H. , Prentice Colin R.M. , McGrouther D. Angus , Sinclair John , McNicol George P. 
Published: June 2018

SummaryAlthough the oral anticoagulants provide effective prophylaxis against postoperative deep vein thrombosis following fracture of neck of femur there is a need for an antithrombotic agent which needs less laboratory control and does not cause haemorrhagic complications. It has been suggested that drugs causing inhibition of platelet function may fulfil these requirements. A controlled trial was carried out in which aspirin, RA 233, or a combination of these drugs was compared with a placebo in the prevention of post-operative deep vein thrombosis. In thirty patients undergoing surgery for fractured neck of femur the incidence of post-operative calf vein thrombosis, as detected by 125I-fibrinogen scanning, was not significantly different between the untreated and treated groups.
Leucocytes and Thrombosis
Authors: Banks D.C , Mitchell J.R.A 
Published: June 2018

SummaryWhen heparinised blood is rotated in a glass flask at 37°C. the white cell count falls and it has been shown that this is due to the adherence and aggregation of polymorphonuclear white cells on the wall of the flask. The masses formed bear a close structural resemblance to thrombi and the mechanisms involved in white cell loss during rotation may therefore increase our knowledge of the thrombotic process.
Chicken Fibrinogen and Human Fibrinogen
Authors: Ménaché Doris , Cesbron Nicole , Guillin Marie-Claude , Schlegel Nicole 
Published: June 2018

SummaryIn order to investigate the immunological features of chicken fibrinogen and to compare them with human fibrinogen, monospecific rabbit antichicken and antihuman fibrinogen antisera have been prepared. Both antisera agglutinated human tanned red cells coated with human fibrinogen. Inhibition of the reaction was obtained by prior incubation of rabbit antichicken fibrinogen antiserum with either human or chicken fibrinogen. Using precipitation reactions in agarose gels, precipitating antigen-antibody complexes were obtained between chicken fibrinogen and rabbit antihuman fibrinogen antiserum and vice versa only if the antisera were concentrated or if an increase in the sensitivity of the reaction was achieved using counter Immunoelectrophoresis. Cross absorption of rabbit antichicken fibrinogen antiserum with human fibrinogen did not abolish the precipitating reaction with chicken fibrinogen. In the same way, cross absorption of rabbit antihuman fibrinogen antiserum with chicken fibrinogen did not abolish the precipitating reaction with human fibrinogen.These results indicate that chicken and human fibrinogen share common antigenic determinants; they also indicate additional antigenic determinants in both fibrinogens.