bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in Platelet Function, Blood Coagulation and Fibrinolysis During Insulin-Induced Hypoglycaemia in Juvenile Diabetics and Normal Subjects
Authors: Dalsgaard-Nielsen J , Madsbad S , Hilsted J 
Published: July 2018

SummaryHaemostatic parameters were assessed before insulin induced hypoglycaemia and 0, 1 and 2 fu after discontinuation of insulin infusion in 7 non-diabetics, aged 28 (22-31) years (mean and range), and 8 juvenile diabetics, aged 3L (27-35) years, with a mean duration of diabetes of 4 years. The patients were normoglycaemic for at least L0 hr before the study.Platelet aggregation in vitro was induced by lower adenosine diphosphate (ADP) concentrations in the diabetics than in the controls before hypoglycaemia and 0 and 60 min after insulin infusion. Platelet counts decreased significantly in the diabetics after hypoglycaemia, whereas no changes were seen in the control group. The activated partial thromboplastin time (APTT) was reduced in both groups and significantly lower in the diabetics than in the controls 120 min after insulin infusion.Fibrinogen and factor VIII R: Ag increased after insulin infusion; highest values were seen in the diabetics. The euglobulin clot lysis time (ELT) was reduced in both groups during insulin infusion; L20 min after end of insulin infusion ELT was significantly longer in the diabetics than in the control group.
Patterns of Adsorption of Proteins From Human Plasma Onto Foreign Surfaces
Authors: Uniyal S , Brash J L 
Published: July 2018

SummaryThe deposition of proteins on blood-contacting surfaces is known to be a determining factor in subsequent thromboembolic events. The composition of the protein layers and how they change with time are unknown. To generate information relevant to these questions, the quantities of albumin, fibrinogen and IgG adsorbed on seven surfaces from human plasma as a function of time were measured using a tracelabeling method. Materials studied include several segmented polyether-urethanes, glass, siliconized glass (SG), polystyrene (PS) and polyethylene (PE).Fibrinogen, surprisingly, was not adsorbed from plasma to any of the hydrophilic surfaces. On PE and SG adsorption passed through an early maximum (before 2 min) then declined to near zero. Only on PS was adsorption substantial and constant with time. Albumin was also not detected on the hydrophilic materials, but was adsorbed substantially on the hydrophobic surfaces. IgG was detected on all surfaces, although in relatively low surface concentrations.These results suggest: 1. that the plasma itself interacts with initially adsorbed proteins, 2. that the role of fibrinogen adsorption in foreign-surface initiated thrombosis may need to be reevaluated and 3. that since the major plasma proteins are only minimally adsorbed, trace proteins may be important in blood-material interactions.
A Clinical and Phlebographie Study of Postoperative Deep Vein Thrombosis Following Knee Meniscus Extirpation
Authors: Nilsen D W T , Westre B , Jaer Ø , Støren G , Jakobsen J Å 
Published: July 2018

SummaryTo evaluate the risk of deep vein thrombosis, a clinical and phlebographic examination was performed 7 to 16 days after a bloodless knee meniscus operation in 37 male patients aged 20 to 35 years. Anticoagulant prophylaxis was not administered. Phlebography revealed asymptomatic calf vein thrombosis in three patients and these were not treated. In two of these phlebography was repeated after six weeks, and complete regression of the thrombi was noted.The present study may underestimate the frequency of postoperative venous thrombosis, as some thrombi may already have lysed at the time of phlebography. However, our results indicate a low incidence of thrombosis after knee meniscus extirpation.
Factor XII and Other Hemostatic Protein Abnormalities in Nephrotic Syndrome Patients
Authors: Thompson Arthur R 
Published: July 2018

SummaryFactor XII clotting activities and antigen levels were assayed in 14 plasma samples from 10 patients with nephrotic syndrome; the group was heterogeneous clinically and histologically. Factor XII was low at initial sampling in 7 of the 10 patients; in 7 of the 14 samples, factor XII antigen was in excess over clotting activity. Inhibition of factor XII could not be demonstrated; excess plasma antigen and urinary antigen (when present) had normal patterns on crossed-immunoelectrophoresis, indicating no major changes in charge or size. In 3 patients tested more than once, plasma levels of factor XII were increased up to 6fold in steroid-induced remission.Of other hemostatic factors assessed for comparison, factor VIII was elevated in 11 of the 14 samples; eight of these had elevated factor VII levels as well. Eight samples from six patients showed low antithrombin III levels; one of these patients had recurrent thromboses. Antithrombin III levels correlated with the serum albumin concentration.Only two of the eight urines tested had detectable factor XII antigen; a third had factor IX and prothrombin and no factor XII. Plasminogen and antithrombin III were readily demonstrated in all urine samples with higher concentrations in those patients with less selective proteinuria. Urinary and plasma levels were not correlated, suggesting that increased consumption or turnover was not simply related to increased filtration.
Reactivity of Fibrinogen Derivatives with Antisera to Human Fibrin D-Dimer and Its γ-γ Chain Remnant
Authors: Cierniewski C S , Janiak A , Nowak P , Augustyniak W 
Published: July 2018

SummaryHighly purified D-dimer was obtained from plasmin digest of human cross-linked fibrin. After reduction of its disulfide bonds, the γ-γ chain remnant, containing cross-linking site, was then isolated by ion-exchange chromatography on CM-cellulose. Antisera obtained by immunizing rabbits with D-dimer and its γ-γ chain remnant contained a small population of antibodies which specifically reacted with D-dimer. Thus, a specific radioimmunoassay system allowing detection and quantitation of D-dimer in the presence of fibrinogen and monomeric fragment D was made possible.
Opposite Effect of Lysine on Platelet Aggregation Induced by Arachidonate and by Other Aggregants
Authors: Ts'ao C , Hart S J , Krajewski D V , Sorensen P G 
Published: July 2018

SummaryEarlier, we found that ε-aminocaproic acid (EACA) inhibited human platelet aggregation induced by adenosine diphosphate (ADP) and collagen, but not aggregation by arachidonic acid (AA). Since EACA is structurally similar to lysine, yet these two agents exhibit vast difference in their antifibrinolytic activities, we chose to study the effect of lysine on platelet aggregation. We used L-lysine-HCl in these studies because of its high solubility in aqueous solutions while causing no change in pH when added to human plasma. With lysine, we repeatedly found inhibition of ADP-, collagen- and ristocetin-induced aggregation, but potentiation of AA-induced aggregation. Both the inhibitory and potentiation effects were dose-dependent. Low doses of lysine inhibited the secondary phase of aggregation; high doses of it also inhibited the primary phase of aggregation. Potentiation of AA-induced aggregation was accompanied by increased release of serotonin and formation of malondialdehyde. These effects were not confined to human platelets; rat platelets were similarly affected. Platelets, exposed to lysine and then washed and resuspended in an artificial medium not containing lysine, remained hypersensitive to AA, but no longer showed decreased aggregation by collagen. Comparing the effects of lysine with equimolar concentrations of sucrose, EACA, and α-amino-n-butyric acid, we attribute the potent inhibitory effect of lysine to either the excess positive charge or H+ and C1− ions. The -NH2 group on the α-carbon on lysine appears to be the determining factor for the potentiation effect; the effect seems to be exerted on the cyclooxygenase level of AA metabolism. Lysine and other chemicals with platelet-affecting properties similar to lysine may be used as a tool for the study of the many aspects of a platelet aggregation reaction.
Thrombin Inhibition and Thrombin Generation by Cultured Aortic Endothelial and Smooth Muscle Cells from Minipig
Authors: Kirchhof B , Grünwald J 
Published: July 2018

SummaryEndothelial and smooth muscle cells cultured from minipig aorta were examined for their inhibitory activity on thrombin and for their thrombin generating capacity.Endothelial cells showed both a thrombin inhibition and an activation of prothrombin in the presence of Ca++, which was enhanced in the presence of phospholipids. Smooth muscle cells showed an activation of prothrombin but at a lower rate. Both coagulation and amidolytic micro-assays were suitable for studying the thrombin-vessel wall interaction.
Activation of Factor IX by Factor XIa - A Spectrophotometric Assay for Factor IX in Human Plasma
Authors: Tans G , Janssen-Claessen T , van Dieijen G , Hemker H C , Rosing J 
Published: July 2018

SummaryThe activation of Factor IX by partially purified Factor XIa was followed by active site titration, gelelectrophoresis and by a spectrophotometric assay. The assay is based on the finding that the rate of Factor X activation in the presence of phospholipid and Ca2+ is linear in time and proportional to the amount of Factor IXa present and can be determined with the chromogenic substrate S2222. Conditions were found that allowed complete activation of Factor IX in human plasma by Factor XIa. The amount of Factor IXa present in the plasma sample can be determined with the spectrophotometric assay and is proportional with the amount of plasma present. In plasma from patients receiving vitamin-K antagonists reduced Factor IX activity is found with the spectrophotometric assay, and the new assay method may be useful in monitoring oral anticoagulant therapy.
Effect of Pyridoxal 5'-Phosphate (PALP) on Human Platelet Aggregation, Dense Granule Release and Thromboxane B2 Generation - Role of Schiff Base Formation
Authors: Krishnamurthi S , Westwick J , Kakkar V V 
Published: July 2018

SummaryPyridoxal 5’-phosphate (PALP) inhibited ADP, thrombin, adrenaline, PAF and AA induced aggregation and 14C-5HT release. Thromboxane B2 (TxB2) generation induced by all the above agents except AA was also inhibited indicating that PALP may be inhibiting AA release via phospholipase A2 activation rather than AA metabolism. PALP inhibited ristocetin induced aggegation in PRP and agglutination in formaldehyde-treated washed platelets (FWP). Inhibition of ADP, adrenaline, PAF and AA-induced aggregation and 14C-5HT release by PALP was found in resuspended platelets pretreated with PALP and sodium borohydride suggesting that inhibition was mediated by Schiff base formation with platelet surface amino groups.Irreversible fixation of PALP to the platelet membrane by borohydride reduction also inhibited thrombin induced 14C-5HT release and TxB2 generation but not thrombin induced primary aggregation or ristocetin induced agglutination in FWP. This suggests that PALP may interact with specific glycoproteins on the platelet membrane involved in ADP, adrenaline and PAF induced primary aggregation and that PALP could be inhibiting ristocetin induced agglutination by direct interaction with ristocetin or FVIII RCoF.
The Incidence of Deep Venous Thrombosis in Patients with an Acute Myocardial Infarction Treated with Acenocoumarol or Indobufen
Authors: Peters S H A , Jonker J J C , de Boer A C , den Ottolander G J H 
Published: July 2018

SummaryIn a randomized double blind clinical trial, we compared indobufen, an antiplatelet drug, with acenocoumarol for the prevention of deep venous thrombosis (D. V. T.) in patients with acute myocardial infarction. Therapy was started on admission and continued for 10 days. All patients were screened daily with impedance plethysmography (I.P.G.) and 125I-fibrinogen leg scanning. Diagnosis of D.V.T. was made when either one or both tests became positive. 74 patients were randomized to treatment with indobufen (200 mg b.i.d.) and 76 patients to acenocoumarol (controlled by thrombotest). The incidence of venous thrombosis in patients with indobufen was 11% and in those treated with acenocoumarol 9%. Major bleeding was observed in 2 patients treated with acenocoumarol. In the indobufen group, no bleeding complications or other serious side-effects were observed. The majority of patients developed thrombosis after the first week of admission. For patients with and without thrombosis, there was no significant difference between the two treatment groups concerning the age, the coronary prognostic index, the maximum C.P.K. value, mobility, incidence of congestive heart failure and the site or extent of the infarct. In this study no clinical or laboratory (fibrinogen, platelet count and anti-thrombin III) parameter, either alone or in combination, was of predictive value for the development of D.V.T. It can be concluded that indobufen appears to be as good as acenocoumarol for the prevention of D.V.T. in patients with acute myocardial infarction. Because it is safe and easy to administer, indobufen seems to be preferable. Prophylaxis is required for at least 10 days.
Kinetics of the Inhibition of Plasmin in Acidified Human Plasma
Authors: Lijnen H R , Maes M , Castel M , Samama M , Collen D 
Published: July 2018

SummaryAcid-treated human plasma is a competitive inhibitor of the hydrolysis of D-Val-Leu-Lys-Nan (S-2251) by plasmin. The rate of hydrolysis is decreased to 50% by 750 fold diluted acidified normal plasma and by 60 fold diluted acidified α2-antiplasmin depleted plasma (α2-antiplasmin concentration less than 2%). These findings suggest that α2-antiplasmin is a contributary but not the main competitive inhibitor of acidified plasma. This interpretation is supported by the finding that α2-antiplasmin depleted plasma reconstituted with purified α2-antiplasmin inhibits the hydrolysis of S-2251 by plasmin at a 125 fold dilution following acidification and by the finding that in a purified system acid inactivated α2-antiplasmin inhibits the hydrolysis of S-2251 by plasmin with a Ki of 25 nM. Thus, besides α2-antiplasmin, other plasma proteins which are at least in part eliminated by the removal of α2-antiplasmin from plasma by immunoadsorption appear to be competitive inhibitors for plasmin in acidified plasma. It is suggested that several competitive inhibitors for plasmin are present and/or generated in acidified plasma and that these inhibitors may at least in part be responsible for the variability in the results of measurements of plasminogen and/or plasmin in plasma following acidification.
Purification of Human Tissue-Type Plasminogen Activator in Centigram Quantities from Human Melanoma Cell Culture Fluid and Its Conditioning for Use In Vivo
Authors: Collen D , Rijken D C , Van Damme J , Billiau A 
Published: July 2018

SummaryHuman tissue-type plasminogen activator was produced in centigram quantities from 50–60 1 batches of conditioned medium of a human melanoma cell culture. The yields of the procedure remained essentially unchanged during 50 subsequent preparations. The final products were of high purity as assessed by SDS gel electrophoresis.These materials, after filtration on 0.22 μM Milliporefilters were sterile and free of viruses and pyrogens. Their stability was very good in the fluid form at temperatures up to 56° C. Material obtained by the present procedure has been used to investigate the biological and thrombolytic properties of tissue-type plasminogen activator.
Platelet Inhibitory Drugs: An In Vivo Method of Evaluation in Patients
Authors: Norcott H C , Goldman M , Hawker R J , Rafiqi E I , Drolc Z , McCollum C N 
Published: July 2018

SummaryThe measurement of platelet deposition in human thrombi is essential for the evaluation of platelet-inhibitory drugs and prosthetic materials for use in patients. The rate of 111Indiumlabelled platelet accumulation on Dacron arterial grafts was measured in 27 patients randomised to take either aspirin and dipyridamole (ASA + DPM) or placebo. Autologous platelets were labelled and re-injected seven days following surgery and the graft thrombogenidty index calculated as the daily rise in the ratio of emissions from the graft over a reference site.The mean (± SD) thrombogenidty index in 12 patients undergoing femoro-popliteal bypass was 0.25 ± 0.09 on placebo and 0.16 ± 0.07 on ASA + DPM started pre-operatively (p Ã0.05). Post-operative ASA + DPM therapy started two days following platelet labelling in 15 patients with aorto-femoral grafts also significantly reduce thrombogenidty to 0.12 ± 0.05 compared with 0.25 ± 0.08 on placebo (p Ã0.01). In the latter patients the ratio of emissions from the graft over reference fell significantly on starting ASA + DPM, suggesting a net loss of platelets from the graft. These results indicate that the rate of in vivo platelet accumulation on Dacron grafts can be quantitated and that ASA + DPM reduced this rate in man.
The Suitability of Various Plasmin Preparations for the Functional Assay of α2-Antiplasmin in Plasma
Authors: Kluft C , Traas D W , Jie A F H , Nobel E Hoegee-de 
Published: July 2018

SummaryVarious plasmin preparations were tested for their suitability for use in the assay of α2-antiplasmin in blood plasma by the immediate plasmin inhibition test.Activation of plasminogen, viz., 1-Glu-plasminogen and/or 77-Lys-plasminogen, by immobilized urokinase results in plasmin preparations suitable for this α2-antiplasmin test. Plasmins obtained by »spontaneous« activation procedures in glycerol containing solutions, however, appeared not to be suitable. In this second group, the behaviour of the plasmins resembles that of 442-Val-plasmin (miniplasmin), which is known to show a low inactivation rate with α2-antiplasmin due to the absence of lysine-binding sites in the plasmin molecule.Evidence is presented that, in the nonsuitable plasmins, the lysine-binding sites, although not completely absent, have at least partly lost their functional integrity.
Platelet Aggregation in Whole Blood Determined Using the Ultra-Flo 100 Platelet Counter
Authors: Fox S C , Burgess-Wilson M , Heptinstall S , Mitchell J R A 
Published: July 2018

SummaryThe Ultra-Flo 100 Whole Blood Platelet Counter has proved a useful tool for measuring platelet aggregation in whole blood, the extent of aggregation being deduced from the number of single platelets that remain. The technique has allowed us to show that platelets aggregate spontaneously in citrated blood and in heparinized blood but not in whole blood collected into EDTA. The aggregation occurs during storage but its rate is enhanced by stirring and it occurs more readily when the whole blood has been exposed to plastic rather than glass. It occurs much more readily in whole blood from some individuals than from others and the process may involve adenosine diphosphate (ADP). The rate of aggregation in whole blood is enhanced by several aggregating agents including collagen, ADP and sodium arachidonate which are more usually studied in platelet-rich plasma.
Platelet Microtubules in Clot Structure Formation and Contractile Force Generation: Investigation of a Controversy
Authors: Jen C J , McIntire L V 
Published: July 2018

SummaryWhether platelet microtubules are involved in clot retraction/ contraction has been controversial. To address this question we have simultaneously measured two clotting parameters, clot structural rigidity and isometric contractile force, using a rheological technique. For recalcified PRP clots these two parameters began rising together at about 15 min after CaCl2 addition. In the concentration range affecting microtubule organization in platelets, colchicine, vinca alkaloids and taxol demonstrated insignificant effects on both clotting parameters of a recalcified PRP clot. For PRP clots induced by adding small amounts of exogenous thrombin, the kinetic curves of clot rigidity were biphasic and without a lag time. The first phase corresponded to a platelet-independent network forming process, while the second phase corresponded to a platelet-dependent process. These PRP clots began generating contractile force at the onset of the second phase. For both rigidity and force parameters, only the second phase of clotting kinetics was retarded by microtubule affecting reagents. When PRP samples were clotted by adding a mixture of CaCl2 and thrombin, the second phase clotting was accelerated and became superimposed on the first phase. The inhibitory effects of micro tubule affecting reagents became less pronounced. Thrombin clotting of a two-component system (washed platelets/ purified fibrinogen) was also biphasic, with the second phase being microtubule-dependent. In conclusion, platelet microtubules are important in PRP clotted with low concentrations of thrombin, during which fibrin network formation precedes platelet-fibrin interactions. On the other hand they are unimportant if a PRP clot is induced by recalcification, during which the fibrin network is constructed in the presence of platelet-fibrin interactions. The latter is likely to be more analogous to physiological processes in vivo.
Prophylaxis of Thromboembolic Disease and Platelet-Related Changes Following Total Hip Replacement: A Comparative Study of Aspirin and Heparin-Dihydroergotamine
Authors: Alfaro M J , Páramo J A , Rocha E 
Published: July 2018

SummaryA prospective study involving 120 consecutive patients undergoing total hip replacement was performed to compare the effectiveness of aspirin (high and low dose) or a combination of heparin plus dihydroergotamine (heparin-DHE) in preventing isotopic and phlebographic deep vein thrombosis (DVT), and to evaluate their effect on postoperative platelet changes. Phlebographic DVT was demonstrated in 9 cases (30%) in control group, in 1 (3.3%) in aspirin (high-dose) group (p <0.01), in 1 (3.3%) in aspirin (low-dose) group (p <0.01) and in 5 (16.6%) in heparin-DHE group (p = NS). Aspirin was able to reduce the postoperative increase in circulating platelet aggregates, platelet factor 4 and p-thromboglobulin observed in control group. This study shows that aspirin is effective in the prevention of DVT for patients undergoing total hip replacement. Small aspirin dose (250 mg/day) represents an effective form of prophylaxis in these patients.
Megakaryocytes from the Marrow of a Patient with Glanzmann’s Thrombasthenia Lacked GPII b-III a Complexes
Authors: Hourdillé P , Fialon P , Belloc F , Namur M , Boisseau M R , Nurden A T 
Published: July 2018

SummaryAlthough it is recognized that glycoprotein (GP) IIb-IIIa complexes are deficient in platelets in Glanzmann’s thrombasthenia, little is known of the origin of the defect. We have examined the megakaryocytes in a bone marrow aspirate obtained from a thrombasthenia patient during surgery. Analysis of platelet proteins by SDS-polyacrylamide gel electrophoresis confirmed the patient to be of the type I subgroup. The megakaryocytes were examined by immunofluorescence or by immunocytochemical procedures combined with electron microscopy. Antibodies used included the murine monoclonal antibody, AP-2 and the human allo-antibody, IgG L, both of which recognize determinants on GP IIb-IIIa complexes. Bound antibody was detected by anti-IgG antibodies coupled to fluorescein isothiocyanate or adsorbed on gold particles. In the immunofluorescence studies, permeabilized megakaryocytes were identified by double staining using an antibody to von Willebrand factor (vWF). Whereas mature megakaryocytes and their small precursor cells from normal individuals were strongly fluorescent with AP-2 and IgG L, most vWF positive cells from the Glanzmann’s thrombasthenia patient were negative and the remainder gave but a weak background fluorescence. Immunogold staining on the surface of marrow cells was severely reduced. Our results confirm a deficiency of GP IIb-IIIa complexes in megakaryocytes in thrombasthenia.