bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variations in Quantitative Ristocetin Platelet Aggregation (RPA) with Time after Platelet Rich Plasma (PRP) Preparation: Association with Alteration in pH
Authors: Coller B. S. , Gralnick H. R. 
Published: June 2019

Decreased quantitative RPA of PRP is used to distinguish patients with von Wille-brand’s disease from normals and hemophiliacs. We observed that RPA (1.8 mg/ml final concentration) of PRP from 9 normals varied markedly with time after PRP preparation. In 6/9 the initial RPA was greatest and decreased progressively with time. In 3/9 RPA increased over the first half hour and then decreased progressively. The decrease from peak values was 37 ±12% (mean±1 SD) at 1 hr, 69 ±20% at 2 hr and 70±10% at 2.5 hr.Several data suggest a role for pH in this phenomenon: (1) pH of the PRP’s increased with time and the decreases in RPA paralleled the increases in pH (2) maintaining the PRP under a 5% CO2-95% O2 atmosphere prevented the rise in pH and lessened the decrease in RPA over time (3) rapidly increasing the pH to 8.3 by bubbling nitrogen through the PRP or titrating with base decreased RPA (81% and 55%) (4) immediate back titration restored the RPA.We conclude that quantitative RPA changes with time after PRP preparation and this is probably in part a function of pH. Since pH change with time is variable for different PRP preparations, choosing an arbitrary time limit after PRP preparation for performing studies is an inadequate control. Quantitative RPA should be pH controlled.
Inhibition of Bovine Factor VIII and Ristocetin Plus Human Factor VIII Induced Platelet Agglutination by Small Peptides
Authors: Macfarlane D. E. 
Published: June 2019

The antibiotic ristocetin induces platelet agglutination in the presence of human factor VIII. A similar agglutination is induced by bovine factor VIII without ristocetin. This antibiotic binds C-terminal D-alanine peptides including the nucleotide-N-acetyl-muramyl-peptide precursor of bacterial cell walls. The effect of several peptides on the agglutination of formalin fixed washed human platelets was investigated. At 1.25 mM acetyl-glycyl-D-alanine (AGDA) and diacetyl-L-lysine-D-alanine-D-alanine (ALAA) increased the amount of ristocetin required for agglutination in the presence of purified human factor VIII; both these peptides bind to ristocetin (Bichochem. J. 124, 845). Glycyl-L-alanine (GLA) glycyl-D-alanine (GDA), acetyl-glycyl-L-alanine (AGLA) were inactive. AGLA (0.25 mM) and AGDA (1.25 mM) inhibited purified bovine factor VIII induced agglutination, ALAA, GLA and GDA (3.2 mM) were inactive.These results suggest that ristocetin acts in part by binding to peptides on the platelet surface, and that bovine VIII combines to the same site but has a different specificity. Suitable small peptides may be able to induce a von Willebrand like state for therapeutic purposes.(Dr. Kirby, Temple University provided the purified factor VIII’s and Prof. Perkins, Liverpool University provided ALAA; supported by N. I. H. HL 14217.)
Estimation and Characterization of Soluble Fibrin monomer Complexes (SFMC) During Endotoxin Induced Disseminated Intravascular Coagulation (DIC)
Authors: Hafter R. , Hugo R. von , Müller-Berghaus G. , Graeff H. 
Published: June 2019

The generalized Shwartzman reaction was produced in rabbits by two injections of endotoxin 24 hours apart. Blood was taken before the first and second injection and 1 and 4 hours after the second injection. SFMC and fibrinogen were precipitated from plasma with β-alanine. Agarose gel filtration resulted in a separation of SFMC and fibrinogen. This enabled an estimation of the SFMC concentration. The per cent amount of SFMC of the total fibrinogen content increased from 5.6±1.8 to 22.9±5.1 per cent (mean±SD) at the end of the collection period. SDS-polyacrylamide gel electrophoresis was performed of SFMC before and after reduction with mercaptoethanol. SDS and urea resistant oligomers could be demonstrated at the time when glomerular fibrin depositions were present. Chain analysis of SFMC revealed γ–γ dimers and a loss of α-chains in association with faster migratin components. This experimental observation indicates that hypercoagulability (before the second endotoxin injection) is accompanied by an elevated level of SDS and urea non resistant SFMC, whereas DIC (last sample) is evidenced by the occurrence of SDS and urea resistant SFMC containing γ—γ dimers.(Supported by DFG, SFB 51, grant no. 2/Gra - B/6.)
Artificial Surfaces - Their Importance with Respect to Generation of Microparticles in Stored Blood
Authors: Eckert G. , Ey G. , Eisert W. G. , Stangel W. 
Published: June 2019

Pulmonary microembolism is a known complication of massive blood transfusion. The development of amorphous microparticles in stored blood depends on numerous factors such as time of storage, the kind of stabilisator, and electrical potential as well as morphology of artificial surfaces of blood containers.We have investigated the surfaces of glass and of different plastics used in Western Europe when taking and preserving blood with a scanning microscope. Clear differences have been observed among the different surfaces of plastic tubes and bags with respect to morphology. With increasing roughness there is increasing incidence of irritated thrombocytes adhearing to the surfaces, augmented adhesivness of thrombocytes, and activation of the blood coagulation system. An increase of both amount and size of microparticles as measured by a laser absorption technique, has also been observed.Our results show that the chosen plastics, as well as the way they are produced, effects the generation of microparticles in stored blood.
Haemostatic Changes Induced in Vitro by Activated Charcoal Haemoperfusion
Authors: Winchester J. F. , MacKay J. M. , Forbes C. D. , Blakely E. , Prentice C. R. M. , Kennedy A. G. 
Published: June 2019

An in vitro system was devised to investigate abnormalities of haemosbasis induced in human blood by haemoperfusion through activated charcoal particles. The system consisted of identical polypropylene columns filled with either uncoated or polymer coated activated charcoal particles, blood being pumped through the system at a constant flow rate, for two hour periods.When sodium citrate was used as the anticoagulant, the fall in platelet count was not statistically different whether coated or uncoated charcoal was used, or whether an empty (saline filled) column was used. However, coated charcoal significantly improved the changes in KCCT, PTT, OSPT, induced by haemoperfusion. Similarly the polymer coating appeared to minimise the fall in fibrinogen, factors II, V, VII, VIII, IX, X, XI, and XII.When mucous heparin (3 μ/ml) final concentration) was used as anticoagulant, massive (80%) retention of platelets occurred with uncoated charcoal, whereas, polymer coated charcoal resulted in only 30% platelet drops.These results suggest that haemostatic abnormalities induced by charcoal haemoperfusion are in part due to contact activation, coagulation factor adsorption, and/or heparin adsorption. Preliminary experiments with heparinised red cell free blood (PRP) have shown minimal platelet drops whether uncoated or coated charcoal was used, suggesting that red cell ADP release may play a crucial role in producing the haemostatic abnormalities, occurring with whole blood haemoperfusion.
Purification and Characterization of Activation Fragments F1 and F2 from Human Prothrombin
Authors: Ball A. P. , Fenton J. , Aronson D. L. , Franza R. B. , Young A. M. 
Published: June 2019

Considerable quantities of the non-thrombin portions of human prothrombin (II) have become available as a byproduct of the large-scale production of human thrombin (Biochim. Biophys. Acta 229, 26). Components not adsorbed on CG-50 are further purified by DEAE-cellulose chromatography and gel filtration, yielding the NH2-terminal fragment (F1) and the inner fragment (F2) which are homogeneous by SDS gel electrophoresis. SDS gel electrophoresis of reduced F1 indicates variable amounts of a two-chain derivative, F1’, with one chain migrating just ahead of F1 and one just ahead of the thrombin A-chain. The F1 → F1’ conversion is catalyzed by thrombin with the creation of a new MH2-terminal threonine. Ultracentrifugal patterns of human F1 and F2 closely resemble those of the bovine fragments. NH2-terminal residues were found to be alanine (± threonine) for F1 and serine for F2. Minor deviations from the reported amino acid compositions of bovine F1 and F2 were observed, primarily in the acidic residues. Other properties include:Immunization of rabbits with F1 gave a precipitating antibody to F1 which cross-reacts with II, but native F2 does not appear to be immunogenic. 3H-F1 is rapidly cleared from the blood of rabbits (T 1/2 20 min), with a major portion detectable in the urine.
The Isolated Surface Membrane of Pig Platelets. I. Subcellular Analysis and Identification Using em Morphometry and 125I Antibody Labelling
Authors: Bullock G. R. , Baker J. R. J. , Taylor D. G. 
Published: June 2019

Platelet membrane vesicles can be separated into two subfractions by centrifugation through a linear sucrose density gradient using the B14 titanium zonal rotor (Taylor and Crawford, 1974). The basis of this subfractionation is the separation of two phosphodiesterase activities. Evidence confirming that the membrane subfraction showing 8-fold enrichment of phosphodiesterase activity towards bis (p-nitrophenyl) phosphate contains surface membrane has been derived from a study of the distribution of 125I after prelabelling the whole cells with iodinated anti-platelet membrane antibody.The circle analysis method of Williams (1969) was used to correlate the distribution of 125I with constituent organelles. This gave a p value of 0.001 and χ2 of 92.8 for the analysis and a high correlation of label associated with the plasma membrane and its elements.
References: Taylor, D. G. and Crawford, N. FEBS Letters, 41, 317-322, 1974. Williams, M. A. (1969) “Advances in optical and electron microscopy”. (R. Barer and V. E. Cosslett, eds.) 3, 219-272. Academic Press London & N.Y.
The Uptake of Adenine by Isolated Human Platelet Membranes
Authors: French P. C. , Sixma J. J. , Holmsen H. 
Published: June 2019

Adenine uptake into isolated platelet membranes had about the same Km (181±21.9 nM) as uptake into intact platelets (151 ±21 nM) and was also competitively inhibited by papaverine and hypoxanthine. No uptake occured at 0° and accumulated adenine was converted to AMP. AMP was not bound to protein as judged by chromatography of triton X-100 solubilized membranes chromatographed on Sephades G-25. The pH optimum for adenine uptake was atpH 5.5. Exogenous 5-phosphoribosyl-l-pyrophosphate stimulated uptake.These data may be explained by uptake of adenine by facilitated diffusion followed by conversion to AMP by adenine phosphoribosyltransferase (E.C. 2.4.2.7.) but group translocation cannot be entirely excluded.
Postoperative Deep Vein Thrombosis
Authors: Gordon-Smith I. C. 
Published: June 2019

Subcutaneous heparin therapy has been shown in several recent studies to be an effective agent in the prevention of postoperative deep vein thrombosis (DVT). However, DVT has not been abolished by such therapy and an increase in haemorrhagic complications, notably wound haematomata, has been reported after its use.In an ongoing double blind randomised controlled study the effects of heparin on DVT and postoperative complications have been correlated with blood heparin levels. Thus far some fifty patients have been studied with the following preliminary conclusions :(I) Subcutaneous heparin administration results in markedly variable blood levels,being maximal two hours after injection at between 0.01-0.30 I.U./ml. (II) 12-hourly injections of 5000 I.U. heparin did not have a cumulative effect over one week.(III) Of seven patients with blood heparin levels in excess of 0.2 I.U./ml, four developed a wound haematoma. Of seventeen patients with blood heparin levels of less than 0.2 I.U./ml only two patients developed this complication.(IV) Thus far 125I-Fibrinogen detected DVT has not occurred in the heparin treated patients.
Coagulation Studies in C4-Deficient Guinea Pigs
Authors: Dodds W. J. , Raymond S. L. , Moynihan A. C. , Pickering R. J. , Amiraian K. 
Published: June 2019

Coagulation and complement parameters of our colony of NIH-multipurpose strain, C4-deficient guinea pigs were compared to those of our age- and sex-matched control guinea pigs (Hartley strain). In addition to very low (< 1 unit) C4 levels, the deficient pigs had significantly lowered CI and C2 activities. Terminal complement component (C3-C9) activity was similar in both strains of animals. Relative to the control population, C4-deficient pigs had significantly higher leukocyte and platelet counts, and more active clot retraction; lower α1- and β2-globulins; prolonged partial thromboplastin and short prothrombin consumption times; and reduced factor VIII activity. Some sex-related differences, such as increased factor XI levels in C4-deficient females, were also observed. Whole blood-clotting and clot lysis times, fibrinogen and plasminogen levels, and factors II, VII, and X activities were not significantly different.These findings indicate reduced intrinsic coagulation in the C4-deficient animals relative to the controls. The coexistence of complement and coagulation deficiencies further supports the functional relationship between these systems.(Supported in part by USPHS Grant HL-09902 from the National Heart and Lung-Institute, National Institutes of Health.)
Products of Platelet Aggregation and Release as a Chemotactic Factor for Human Leucocytes
Authors: Clawson C. C. , Repine J. E. 
Published: June 2019

Human platelets, doubly washed and resuspended in protein-free balanced saline, were aggregated with bacteria (S. aureus), adenosine diphosphate or collagen. The soluble products of platelet release were separated from the aggregates by centrifugation at 105,000 g for 60 min. Washed human neutrophils in protein-free balanced saline in Boyden chambers were attracted as well by the supernatants of platelet aggregation (297 ± 35) as they were by zymosan-activatedpooled serum (275 ± 12). Ultrasonic disruption of washed, unaggregated platelets failed to release comparable soluble chemotactic components. Control supernatants of unaggregated platelets, bacteria, ADP or collagen and the pellets from aggregated or sonicated platelets all failed to stimulate leucotaxis. Neutrophils incubated with inhibitors of prostaglandin synthesis failed to respond to platelet aggregation products although their random mobility was not impaired. The soluble products of platelet aggregation also stimulated chemotaxis of human eosinophils and monocytes. Neutrophil metabolism of glucose 1-14C was not enhanced by incubation with the supernatants of platelet aggregation. These findings indicate that the leucotactic agent of platelets is a soluble product of physiologic aggregation and release, and that the response of neutrophils to the platelet product is dependent upon prostaglandin synthesis and independent of increased activation of the hexose-monophosphate shunt.(Aided by grants of the NIH and American Heart Association.)
Endothelial and Smooth Muscle Cells as Antagonists in Vascular Fibrinoysis
Authors: Hegt V. Noordhoek 
Published: June 2019

Endothelial plasminogen activator activity in different types of human blood vessels obtained from fifty necropsies and thirty-five biopsies was detected and localized by means of plasminogen-rich fibrin slides. Great differences in endothelial activator activity were found along and across (vasa vasorum) the wall of the human vascular system.The same blood vessels were simultaneously investigated by a modified fibrin slide technique using plasminogen-free fibrin slides covered by plasmin to detect and localize inhibition of fibrinolysis in the vascular wall. The great variation in plasmin inhibition in different vessels revealed by this “fibrin slide sandwich technique” appeared to be closely associated with the localization and number of smooth muscle cells present in the walls of the vascular system. Strong plasmin inhibition was generally found at sites which showed no activator activity with the regular fibrin slide technique, while areas with a high endothelial fibrinolytic activity mostly revealed no inhibitory capacity.These results indicate that much of the variation in endothelial fibrinolytic activity on fibrin slides is due to inhibitory effects from the surrounding smooth muscle cells rather than to variability in the plasminogen activator content of the endothelium itself.
Comparative Investigations on Factor VIII Assays
Authors: Pflugshaupt R. , Moser S. , Züger K. , Bütler R. 
Published: June 2019

Six one stage methods and one two stage method were tested for precision and reproducibility. With each method twenty calibration curves of normal plasma and two lots of Factor VIII concentrates were established. Statistical evaluation revealed only minor differences. Neither one of the methods was optimal for both the physiological-pathological region and the region of high activity preparations.Three selected methods were tested in vivo for accuracy: nine patients with hemophilia A were treated with equal amounts of Factor VIII concentrates or kryoprecipitates respectively. The methods showed different activities for preparations as well as for patient’s plasma. The discrepancy between measured and expected recovery differed for each method.
Automated Techniques for Estimating Factor VIII Levels in Concentrate Preparations
Authors: Seghatchian M. J. , Miller-Anderson M. , Howarth D. J. , Stirling Y. , Brozovic M. 
Published: June 2019

An. automated coagulometer (a modification of Electra 600D) using an optical end-point for clot detection, has been used in both one and twostage methods of assaying factor VIII. Fifity clotting times can be measured in a hour. The methods for which the coagulometer has been used are (1) one-stage assay with kaolin-platelet substitute and haemophilic plasma, (2) one-stage assay with activated cephaloplastin (Dade, Nyegaard) and haemophilic plasma, and (3) two-stage method using combined serum reagent (Diagen). With the first two methods, a shortening of standard and blank clotting times occurred during the hour-long course of the assays (2-5 seconds per hour); this was particularly marked in the presence of kaolin, and due in part to activation of factor VII. With the two-stage method, longer standard and blank clotting times, up to 8 seconds per hour, were often recorded as the assays proceeded. These results emphasize the need to incorporate standards at regular intervals during every run, and to take account of the changes with time that occur.Four different types of concentrate preparations commonly used in the treatment of haemophilia were assayed in two laboratories, each using conventional and automated (Electra 600D) methods. There was good agreement between methods and between laboratories.
A More Uniform Measurement of Factor VIII Inhibitors
Authors: Kasper C. K. , Aledort L. , Aronson D. , Counts R. , Edson J. R. , Eys J. v. , Fratantoni J. , Green D. , Hampton J. , Hilgartner M. , Levine P. , Lazerson J. , McMillan C. , Penner J. , Shapiro S. , Shulman N. R. 
Published: June 2019

A group of hematologists, involved with hemophilia research and care in the U.S.A., met under the sponsorship of the Division of Blood Diseases and Resources of the National Heart and Lung Institute. In order to improve future communication among ourselves, we decided to alter our individual methods of measurement of inhibitors to the extent necessary to permit a uniform, although arbitrary, description of inhibitor units. We agreed to the following standards: (1) The incubation mixture consists of one part citratecl patient plasma, undiluted or diluted, plus an equal part of citrated pooled normal human plasma. (2) A control incubation mixture consists of equal parts of normal pooled plasma and imidazole buffer, as formulated by Dr. Biggs. (3) The mixtures are incubated at 37° C for two hours. (4) Assays specific for Factor VIII are then performed and the Factor VIII activity in the patient mixture is divided by the Factor VIII activity in the control mixture to determine the percent residual Factor VIII activity. (5) A patient plasma giving a residual Factor VIII activity of 50 percent in this test is said to contain one “Bethesda unit” of inhibitor per ml. (6) On a graph, the log percent residual Factor VIII activity is plotted against inhibitor units. If the residual Factor VIII activity of the incubation mixture is between 75 and 25 percent, the inhibitor units are read from the graph. Plasmas containing strong inhibitors are diluted with imidazole buffer before being placed in the incubation mixture. A dilution is sought which will result in a residual Factor VIII activity between 75 and 25 percent. The units of inhibitor read from the graph are then multiplied by the dilution factor to determine the number of Bethesda units of inhibitor per ml of undiluted patient plasma.We invite interested colleagues to join us in the use of this method, and we invite discussion of better methods of describing inhibitor potency.
Prophylaxis of Deep Vein Thrombosis after Total Hip Replacement
Authors: Rosengarten David S. , McNeur J. Clarke 
Published: June 2019

In a prospective randomized study designed to compare the effectiveness of intraoperative electrical calf stimulation, perioperative low dosage heparin, and aspirin, either alone or in combination, as prophylactic measures for deep vein thrombosis following total hip replacement, the incidence of thrombosis, as diagnosed by the radioactive fibrinogen uptake test in the study groups was: Control – 9 out of 20 (45%); Calf Stimulation – 9 out of 22 (41%); Aspirin – 9 out of 20 (45%); Heparin – 7 out of 21 (33%); Aspirin plus Calf Stimulation – 10 out of 20 (50%); Heparin plus Calf Stimulation – 0 out of 25.Following this study only 2 patients developed thrombosis during the period of heparin administration out of a further 104 consecutive patients given low dosage heparin and calf stimulation. Of these patients, thrombosis occurred within 48 hours of cessation of heparin in 11 out of 52 (23%) given heparin until the tenth postoperative day, and in 7 out of 75 (9% ) given heparin until the 14th postoperative day.Data will be presented to support the following conclusions : 1. The incidence of thrombosis is (i) high (about 50%), (ii) over 50% of thromboses occur either during or soon after operation, (iii) no more frequent in either the operated or non-operated legs. 2. Clinical Diagnosis of thrombosis is grossly inadequate. 3. Prophylaxis is: (i) ineffective with aspirin and calf stimulation, either alone or in combination, or with low dosage heparin alone, (ii) significant with a combination of intraoperative electrical calf stimulation and perioperative low dosage heparin in that the incidence is markedly reduced and the onset delayed the longer the heparin is administered. 4. Low dosage heparin or aspirin does not increase the risk of haemorrhage.