bluuebunny/crossref_metadata_2025 huggingface dataset:
Sialic Acid Dependent Polypeptide Chain Heterogeneity of Human Fibrinogen Demonstrated by Two-Dimensional Electrophoresis
Authors: Kuyas Cemal , Haeberli André , Straub P Werner
Published: July 2018

Human fibrinogen was compared with asialofibrinogen by two-dimensional electrophoresis to evaluate the contribution of sialic acid to the heterogeneity of the γ- and Bβ-polypeptide chains.

Reduced fibrinogen showed three major variants for both the γ- and Bβ-chains. In addition two minor γ-bands with a more acidic isoelectric point than the normal γ-chains were observed. Electrophoresis in the second dimension (SDS) suggests that these most acidic bands are γ-chain-variants with a higher molecular weight. In asialofibrinogen only two predominant variants with more alkaline isoelectric points were present in each chain type.

It is concluded that enzymatic removal of sialic acid partially reduces the heterogeneity of the γ- and Bβ-polypeptide chains of human fibrinogen, but additional sources producing charge heterogeneity must be sought.
An Evaluation of APTT Monitoring of Low-Dose Heparin Dosage in Hip Surgery
Authors: Poller L , Taberner D A , Sandilands D G , Galasko C S B
Published: July 2018

The activated partial thromboplastin time has been used to monitor the effects of low-dose subcutaneous heparin in two groups of patients undergoing hip surgery. The study was performed to determine the degree of anticoagulation required to protect these high-risk patients from post-operative deep vein thrombosis. The patients were randomised to receive a fixed regimen of subcutaneous calcium heparin (5,000 units eight-hourly) or a dose of calcium heparin monitored by maintaining the standardised APTT at 50 secs. In the adjusted group the APTT achieved the target figure in 46% of observations compared to 27% in the fixed group (p μ0.005). Nine patients showed positive 125I-fibrinogen scans and in all, the APTT was below the target value the day before the scan became positive. In contrast, in six of the nine thrombotic patients heparin was detected by antifactor Xa clotting assay. The APTT, therefore, appears to give a better guide to the antithrombotic effect of heparin than the antifactor Xa clotting assay. These preliminary observations suggest that prolonging the standardised APTT method to just above 50 secs improves prophylaxis in high-risk cases. Furthermore, an increased dose of heparin is required than is provided during the conventional low-dose regime of 5,000 units tds. With regular control using the standardised APTT, increasing the dose to the target value does not increase postoperative haemorrhage.

Further studies with larger numbers of patients are required in order to show a significant reduction in the incidence of postoperative deep vein thrombosis in hip surgery patients receiving low-dose adjusted heparin.
Plasma Fibrinopeptide A and Beta-Thromboglobulin in Pre-Eclampsia and Pregnancy Hypertension
Authors: Douglas J T , Shah M , Lowe G D O , Belch J J F , Forbes C D , Prentice C R M
Published: July 2018

Increased plasma levels of β-thromboglobulin (βTG) and fibrinopeptide A (FPA), markers of platelet release and thrombin generation respectively, were measured in normal women, women taking oral contraceptives, normal pregnancy and pregnant women with hypertension or pre-eclampsia. No significant increases in βTG or FPA were found in women taking oral contraceptives. Significantly increased concentrations of βTG, but not FPA, were found in normal pregnant women in the second and third trimester of pregnancy when compared with nonpregnant age-matched controls. In eleven women with pregnancy hypertension and thirteen women with pre-eclampsia significantly elevated levels of both βTG and FPA were found when compared with age, parity and gestation-matched pregnant controls. Although the mean value for both βTG and FPA in the group with pre-eclampsia was higher than the group with pregnancy hypertension, the difference was not statistically significant. These findings provide additional evidence that pre-eclampsia and pregnancy hypertension are associated with activation of the coagulation system and the platelet release reaction.
Successive Factor VIII Doses for a Haemophiliac Undergoing Major Surgery Calculated on a Microcomputer
Authors: Duncan Bruce , Lloyd John , Lesnikowski Elizabeth
Published: July 2018

Doses of factor VIII to be infused into a haemophiliac undergoing major surgery were calculated on a micro-computer. The degree to which the particular patient responded to infused factor VIII and the rate at which it decayed were estimated by two pre-operative experiments. Plasma levels of factor VIII were predicted over fourteen days during which time the patient was infused with 53,000 iu. A continuous plot of predicted values with time was displayed on a video monitor. The predicted values showed good agreement with assay results.
A Comparison of the Bethesda and New Oxford Methods of Factor VIII Antibody Assay
Authors: Austen D E G , Lechner K , Rizza C R , Rhymes I L
Published: July 2018

A collaborative trial has been carried out under the auspices of the International Committee on Thrombosis and Haemostasis to compare the Bethesda and New Oxford methods of antibody assay. It was found that errors between laboratories were much greater than those within laboratories and each laboratory had a bias whereby it always rated samples high or low with respect to the other laboratories. However there was excellent agreement in the order in which laboratories ranked antibody samples and if a standard antibody sample could be provided there would be a significant improvement in numerical agreement between laboratories. On average, for this exercise, a result for a given sample in Bethesda units was 1.21 times the result in New Oxford units although it must be stressed that this ratio could vary from sample to sample.
Biochemical and Metabolic Aspects of Platelet Dysfunction in Chronic Myeloproliferative Disorders
Authors: Pareti F I , Gugliotta L , Mannucci L , Guarini A , Mannucci P M
Published: July 2018

Fifty-two patients with chronic myeloproliferative disorders (13 with polycythemia vera; 23 with primary thrombocythemia; 6 with myelofibrosis and 10 with chronic granulocytic leukemia) had low platelet levels of adenine nucleotides and serotonin and abnormal uptake and storage of the amine. The storage pool deficiency was confined to the substances contained in the platelet dense bodies, because α-granule and lysosome markers were present in normal amounts. In chronic granulocytic leukemia the storage defect was usually less marked but was accompanied by a decreased formation of thromboxane B2 and normal platelet aggregation in response to arachidonic acid. There was no clearcut relationship of these biochemical abnormalities to prolongation of bleeding time or to thrombotic and hemorrhagic symptoms. The defect was still present in 15 patients after treatment had returned the cell counts to the normal range. Normal levels of 5HT and adenine nucleotides were observed in 8 patients whose platelet counts were high after splenectomy for non-hematological reasons. These findings suggest that biochemical abnormalities are related to the presence in the bone marrow of abnormal clones, resulting in the production of defective platelets.
Effect of cAMP Phosphodiesterase Inhibitors on ADP-Induced Shape Change, cAMP and Nucleoside Diphosphokinase Activity of Rabbit Platelets
Authors: Lam S C-T , Guccione M A , Packham M A , Mustard J F
Published: July 2018

The effects of cAMP phosphodiesterase inhibitors on ADP-induced shape change and cAMP concentrations have been studied. Caffeine (10 mM), theophylline (8 mM), dipyridamole (0.2 mM), or papaverine (0.05 mM) prevented the shape change of washed rabbit platelets induced by 0.4 μM ADP. At these concentrations, none of these cAMP phosphodiesterase inhibitors increased 14C-cAMP in platelets in which the cytoplasmic adenine nucleotides had been labelled with 14C-adenine. By a protein binding assay, only papaverine by itself increased platelet cAMP above its basal level. These results indicate that two pools of cAMP may exist in platelets. Both methods showed that stimulation of platelet adenylate cyclase with PGE1 (1 μM) resulted in an increase in platelet cAMP and all these cAMP phosphodiesterase inhibitors potentiated this increase caused by PGE1. By themselves, some of these compounds may act through mechanisms that do not involve platelet cAMP. The effects of these cAMP phosphodiesterase inhibitors on platelet nucleoside diphosphokinase (NDK) activity were also investigated. At concentrations that prevented ADP-induced shape change, papaverine and dipyridamole had no effect on the formation of 14C-ATP from 14C-ADP by washed rabbit platelets. The methylxanthines partially inhibited NDK activity of washed rabbit platelets and of isolated platelet membranes, probably due to the structural similarity between the adenine ring of ADP and these substances. However, adenine (8 mM) inhibited ADP-induced shape change and platelet NDK activity but was a less effective inhibitor of ADP-induced platelet aggregation. Thus it seems unlikely that interference with platelet NDK or the ADP receptor is the major mechanism by which the methylxanthines inhibit platelet functions.
A Comparison of Pentosan Polysulphate (SP54) and Heparin I: Mechanism of Action on Blood Coagulation
Authors: Fischer A-M , Barrowcliffe T W , Thomas D P
Published: July 2018

The effects of SP54 on inhibition of thrombin, factor Xa and factor IXa, in the presence and absence of antithrombin III (At III), have been examined and compared to those of heparin. SP54 potentiated inhibition of thrombin and Xa by purified At III, but crossed immunoelectrophoresis data indicated that these effects were mediated by binding to the enzyme, rather than to At III. Relatively high concentrations of SP54 were required for inhibition of thrombin and Xa in plasma, but at concentrations less than 2 μg/ml there was a marked suppression of the intrinsic activation of factor X. This effect was shown to be independent of At III, and to be due largely to inhibition of factor IXa. Prothrombin activation by factor Xa and phospholipid was also suppressed by SP54 in the absence of At III, and its effect on the APTT was also shown to be independent of At III. It is concluded that at relatively low concentrations the anticoagulant actions of SP54 are mainly due to these At III-independent pathways.
Thrombin Potentiation of Factor VIII Procoagulant Activity: Assessment by the Two-Stage Assay
Authors: Kopitsky Robert G , Switzer Mary Ellen P , McKee Patrick A
Published: July 2018

Factor VIII (FVIII) procoagulant activity is the function of a plasma glycoprotein that is missing or inactive in patients with classic hemophilia. Numerous studies have shown that trace thrombin causes rapid enhancement followed by gradual inactivation of FVIII procoagulant activity. Recent evidence suggests that thrombin activation of the FVIII/von Willebrand factor (vWF) protein is required for inactivation to occur. All of these studies have used the one-stage partial thromboplastin time to assay FVIII activity. Other investigators have used the two-stage assay of FVIII activity and have been unable to demonstrate thrombin-induced enhancement of FVIII activity, although inactivation has consistently occurred. We performed experiments designed to help resolve this disagreement, using the two-stage assay specifically modified to detect thrombin potentiation of FVIII activity. The length of the first-stage incubation time was found to be critical in demonstrating the initial effect of thrombin on FVIII activity. Taking advantage of this finding we were able to show a 4.1 ± 0.5-fold enhancement of FVIII activity upon incubating purified FVin/vWF with 0.04 NIH unit thrombin per ml. The apparent enhancement of FVEQ activity declined with increasing thrombin concentration. Incubation with 0.08, 0.16, and 0.32 NIH unit thrombin per ml resulted in only 3.2 ± 0.5, 2.6 ± 0.5 and 1.5 ± 0.3-fold enhancement, respectively, of FVIII activity. As with results from the one-stage assay, activation was followed by slow inactivation of FVIH/vWF. Using the two-stage assay we also showed 100% inactivation and 100% inhibition of FVIII activity by plasmin and human anti-FVUI IgG, respectively. Plasmin inactivation of FVIII activity showed a dose-response effect. Thrombin was unable to activate plasmin-degraded FVin/vWF. Our results show that thrombin potentiation of FVni activity is easily demonstrable in the two-stage assay. These findings support the contention that activation of FVm activity by thrombin is prerequisite for inactivation and underscore the importance of thrombin activation of FVHI/vWF in the intrinsic clotting system.
Inhibition of Thrombin-Neutralizing Activity of Antithrombin III by Steroid Hormones
Authors: Nagasawa H , Kim B K , Steiner M , Baldini M G
Published: July 2018

Estrogens in high doses have been shown to inhibit, in vitro, the thrombin-neutralizing action of antithrombin III (AT III). In this study we investigate the effect of estrogens on AT III in greater detail. To increase the sensitivity of measurement of AT III activity in the absence of heparin, we have developed an assay system utilizing human platelets, AT III and thrombin. The two proteins derived from human plasma were prepared in high purity. Platelet aggregation was induced by approximately 0.02 NIH U of thrombin. AT III was added in amounts that suppressed 95% of the aggregation-inducing effect of thrombin. Estrogens blocked the thrombin-neutralizing effect of AT III in dose-dependent manner. This effect was shown to be specific for AT III. Neither aggregability of platelets nor aggregating effect of thrombin were affected by the steroid hormone. Evidence for binding of estrogen to AT III was obtained from changes in intrinsic fluorescence of AT III. Activity of AT III was also reduced in increasing order of effectiveness by cholesterol, cortisone, testosterone and progesterone. Our studies suggest a direct effect of estrogens and other steroids on AT III, altering its specific neutralization of thrombin.
Pharmacological Studies on the Antithrombotic Action of Hirudin in Experimental Animals
Authors: Markwardt F , Hauptmann J , Nowak G , Kleßen Ch , Walsmann P
Published: July 2018

The pharmacodynamics and pharmacokinetics of hirudin were studied in dogs, rabbits and rats. Hirudin proved to be a well tolerated substance with low toxicity. After intravenous injection it was eliminated with a half time of 50 to 60 min. It was nearly completely excreted through the kidneys in biologically active form. The efficacy of hirudin in preventing venous thrombosis, vascular shunt occlusion and disseminated intravascular coagulation in rats was demonstrated.
Lipoprotein Fractions and Antithrombin III Consumption During Clotting
Authors: Winter J H , Bennett B , McTaggart F , Douglas A S
Published: July 2018

Plasma and serum antithrombin levels were measured in functional (initial rate measurement) and immunological assays together with serum lipid levels in normal subjects and patients with coronary artery disease. Specific antithrombin activity in plasma showed a negative correlation with triglyceride levels. The consumption of antithrombin activity during blood clotting was negatively correlated with both serum total triglyceride and heparin precipitable lipoprotein and positively correlated with serum high density lipoprotein cholesterol. Different blood lipoprotein fractions may influence the activity of the antithrombin III molecule.
Determination of the Density Distribution of Human Platelets - Methodological Aspects and Comparison with Other Tests for Platelet Activation
Authors: Oost B A van , Hien-Hagg I H van , Veldhuyzen B F E , Timmermans A P M , Sixma J J
Published: July 2018

Stimulation of human platelets to release results in decreased buoyant density. This decreased density provides a tool to detect circulating platelets which have participated in a thrombotic process. Platelet density gradient centrifugation using Stractan was standardized and the effects of anticoagulation, temperature, and osmolarity were investigated. In 7 out of 32 patients with thrombotic disease less dense platelets were found. Platelet activation in the patient group was also indicated by spontaneous aggregation (10/32), decreased circulating platelet aggregate ratios (5/24) and elevated plasma β-thromboglobulin levels (2/11). Several of these tests were also abnormal in diabetes mellitus thrombocytosis, leukaemia and several systemic diseases with thrombotic complications. The platelet density test using Stractan is reproducible and independent of other tests for platelet activation and is therefore potentially a useful extension of platelet function testing in patients with thrombotic disease.
Alteration in Plasma Proteins and Platelet Functions with Aging and Cigarette Smoking in Healthy Men
Authors: Chao F C , Tullis J L , Alper C A , Glynn R J , Silbert J E
Published: July 2018

Blood samples were obtained on four different occasions from 18 cigarette smoking and 34 non-smoking healthy men (age 4Hl9) and analped to assess age- and smoking-associated changes in plasma proteins, btood coagulation and platelet functions. C-ollagen-induced platele t aggregation was signifi cantly inclreased with agng in non-smokers. Significant gfuanges in chronic smokers were increases in platelet count and fibrinogen in plasma; elevation of platelet factor-3 (PF-3) activity in plateletpoor plasma (PPP); increase in serum levels of a1-antitr,?sin, orosomucoid, haptoglobin and properdin factor B; and sfoeftsning of the lag period of collagen-induced platelet aggregation. Filtration of PPP through Mllipore fiIters removed PF-3 membranes. The differen@s in PF-3 activities in fiItered plasma were no longer significant between smokers and non-smokers. Results suggest that chronic smokers have higher levels of acute phase proteins reflecting underlyrng inflammatory processes, and higher levels of PF-3 activity in plasma due to liberation of PF-3 membranes from platelets.
Functional Activities and Concentrations of Plasmin Inhibitors in Normal Subjects and D. I. C. Patients
Authors: Velasco F , Torres A , Andres P , Duran M I
Published: July 2018

Alpha-2-macroglobulin and fast antiplasmin, the main inhibitors of the fibrinolytic system, and the presence of plasmin-antiplasmin complex (P-AP) were studied in 15 DIC patients and in 20 healthy individuals. There was a lack of correlation between immunological and chromogenic substrates alpha-2 antiplasmin levels when P-AP complex were found in DIC patients (in 6/15 cases). The levels of alpha-2-macroglobulin were within the normal range in most of these patients, confirm the secondary role of this inhibitor in fibrinolysis.
The Recovery of Platelet Malondialdehyde Production After a Single Intake of Aspirin - The Effect of Dosage
Authors: Takayama Hiroshi , Okuma Minoru , Uchino Haruto
Published: July 2018

We studied the recovery pattern of platelet malondialdehyde (MDA) formation after a single intake of various doses of aspirin (ASA). In normal subjects, there were striking differences in the recovery pattern between large doses (1,000 or 500 mg) and small doses (100 or 50 mg) of oral ASA. The 2 day lag phase was present in the large dose group which showed the complete inhibition of the circulating platelets 2 hr after oral ASA but not in the small dose group which showed the incomplete inhibition. The difference of recovery time between these two groups was about 2 days. These data suggest that ASA’s effect on megakaryocytes might affect the recovery pattern of MDA formation by the circulating platelets. In 2 patients with chronic idiopathic thrombocytopenic purpura, the 2 day lag phase was not observed in the recovery even after a large ASA dose.
“Lupus” Anticoagulant and Thrombosis – Possible Role of Inhibition of Prostacyclin Formation
Authors: Carreras L O , Vermylen J G
Published: July 2018

A “lupus” anticoagulant was discovered in 14 patients over a one year period. Only three of them had systemic lupus erythematosus. Bleeding manifestations were only present in one patient with concomitant severe thrombocytopenia. In contrast, eight patients had a history of thrombosis; five of them presented repeated thrombotic episodes. Obstetrical complications (recurrent abortion, fetal death, or intrauterine growth retardation) were observed in six patients. An inhibitory effect of plasma on the production of prostacyclin by vascular tissue was detected in eight patients, six of whom had thrombosis. We suggest that inhibition of prostacyclin formation could play a major role in the pathogenesis of thrombosis and obstetrical problems in some patients with this type of anticoagulant, even in the absence of systemic lupus erythematosus.
Catabolism of Purified Rat Fibrin(ogen) Plasmin Degradation Products in Rats
Authors: Nieuwenhuizen W , Emeis J J , Vermond A
Published: July 2018

The blood clearance of purified plasmin degradation products (X, Y, D-dimer, Dcate, D EGTA, E-fibrin, Ecate and E EGTA) of rat fibrin(ogen) has been studied in a homologous system. Transcapillary flux rate constants, fractional catabolic rate constants and the ratios of intravascular and extravascular pools have been calculated. There are considerable differences in these constants between the two early fibrinogen degradation products X and Y. Also the differences between fibrinogen D and E fragments, derived from different parts of the fibrinogen molecule, are considerable. However, the differences between fibrin fragment D-dimer and fibrinogen fragment Dcate are relatively small. Also the differences between fragments E-fibrin, Ecate and EEGTA are small. The main fraction of all E-fragments is extravascular.
Degranulation of Rabbit Platelets with PAF-Acether: A New Procedure for Unravelling the Mode of Action of Platelet-Activating Substances
Authors: Vargaftig B Boris , Joseph Danielel , Marlas Guy , Chevance L-G
Published: July 2018

Aggregation and secretion of ATP induced by thrombin, collagen, the snake venom component convulxin and platelet-activating factor (PAF-acether) were studied after the exposure of rabbit platelets to 1 μM of PAF-acether. This concentration, which is around 6 orders of magnitude above the concentration needed to induce full aggregation, was required to remove most of the releasable ATP from the platelets. The depleted platelets aggregated to PAF-acether, to thrombin and to convulxin under conditions where only very low amounts of ATP were secreted, confirming that these agents do not require the release of dense body components to trigger aggregation. Furthermore, when exposure to PAF-acether was associated to inactivation of platelet cyclooxygenase with aspirin, aggregation to thrombin persisted, validating the claim that thrombin induces aggregation by a third pathway unrelated to ADP and to thromboxane A2. Aggregation by collagen was markedly reduced by exposure of the platelets to PAF-acether or to aspirin; when both procedures were associated, aggregation was suppressed. Failure to desensitize the rabbit platelets to PAF-acether upon exposure to high amounts of it indicates the absence of irreversible membrane changes due to PAF-acether, and allows its use as a depleting procedure for the dense body materials, which does not affect platelet membrane components as is the case for thrombin.
On the Reliability of the Use of Heparin Immobilized on Agarose for the Study of the Interactions among Heparin, Thrombin and Antithrombin
Authors: Fish Wayne W , Björk Ingemar
Published: July 2018

The extent of inhibition of thrombin was re-examined as a consequence of the sequence of addition of thrombin and antithrombin III to a column of heparin immobilized on agarose. With the use of pure enzyme, pure inhibitor, and a highly sensitive chromogenic substrate, no appreciable difference in the extent of thrombin inhibition was observed between the two sequences of addition. These observations, together with a demonstrated sensitivity of the method to variations in experimental protocol, challenge the conclusions reached in an earlier work (Hatton and Regoeczi, Thromb. Res. 1977; 10:645) which utilized this experimental approach but which employed larger quantities of reactants and a less sensitive substrate.
Response of Factor VIII/Von Willebrand Factor to Intranasal DDAVP in Healthy Subjects and Mild Haemophiliacs (with Observations in Patients with Combined Deficiency of Factors V and VIII)
Authors: Garcia V Vicente , Silva I Alberca , Borrasca A Lopez
Published: July 2018

The effect of a single standard dose of intranasal DDAVP (260 μg) was investigated in healthy subjects and in patients with mild deficiencies of VIII:C. Changes in FVIII/VWF activities were measured from baseline after 30, 60, 120 and 360 min of administration of the drug. Intranasal DDAVP was followed by a two-fold increase of VIII:C in both groups studied. VIIIR : AG and VIIIR:RCo increased to a lesser extent. Even though FVIII/VWF activities reached their maximum after 60–120 min, a significant increase over baseline was still observed after 360 min. The rise of VIII:C was unrelated to the body weight of the patients and was proportional to the baseline levels of this factor. In two sisters with combined deficiencies of FV/FVIII, the responses in all activities of FVIII/VWF were similar to those seen in mild hemophiliacs. Factor V did not undergo any variation. No alteration in serum osmolarity and no consistent variation in blood pressure or pulse rate were noted. It is concluded that the i.n. administration of a single high dose of DDAVP might be adopted to provide an emergency aid in bleeding patients with mild to moderate haemophilia A and to yield higher VIII:C levels in blood donors.
Bleeding Time in Rats: A Comparison of Different Experimental Conditions
Authors: Dejana Elisabetta , Villa Silvia , de Gaetano Giovanni
Published: July 2018

The tail bleeding time (BT) in rats definitely varies according to the method applied. Of the various variables that may influence BT, we have evaluated the position (horizontal or vertical) of the tail, the environment (air or saline), the temperature (4°, 23° or 37° C) and the type of anaesthesia. Transection of the tail tip cannot be used to screen drugs active on platelet function since it is sensitive to coagulation defects. Template BT in contrast is not modified by heparin and is sensitive to defects of platelet number and function (“storage pool disease”, dipyridamole-like drugs, exogenous prostacyclin). In contrast the test fails to detect aspirin-induced platelet dysfunction. The evidence reported indicates that thromboxane A2-prostacyclin balance is not a factor regulating BT. Aspirin treatment however may be a precipitating factor when associated with other abnormalities of platelet function.

Template BT is a valid screening test for platelet disorders and for antiplatelet drugs.
Platelet Hyperaggregability in Ischemic Cerebrovascular Disease and Effects of Aspirin
Authors: Kusunoki M , Kimura K , Nagatsuka K , Isaka Y , Uyama O , Yoneda S , Abe H
Published: July 2018

Platelet aggregation was studied in 24 patients in the chronic stage of ischemic cerebrovascular disease (CVD), with cerebral affluent and effluent blood, i.e., carotid arterial and internal jugular venous blood, and also with peripheral venous blood. Aggregation tests were performed at various final concentrations of sodium arachidonate (A.A.) and ADP. In 17 patients, not taking aspirin, platelet aggregability in jugular venous blood was significantly accentuated compared with that in arterial and peripheral venous blood. This tendency was more marked in the patients with cerebral artery stenosis and/or occlusion than in those with normal cerebral angiogram. In 7 patients taking 500 mg or more oral aspirin, aggregation differences across the brain were not observed and A.A. aggregation and the second phase of ADP aggregation were completely suppressed. These results suggest that a prophylactic administration of aspirin may be beneficial for patients in chronic stage of CVD.
In Vivo Platelet Activation Following Myocardial Infarction and Acute Coronary Ischaemia
Authors: Hughes A , Daunt S , Vass G , Wickes J
Published: July 2018

Forty-seven patients presenting with acute chest pain had in vivo platelet activity assessed by measuring plasma levels of the platelet-specific protein beta thromboglobulin (BTG), and by screening for the presence of circulating platelet aggregates. Nineteen patients with transmural myocardial infarction (MI), 21 patients with acute coronary ischaemia (CI), and 7 patients with non-cardiac chest pain (NCCP) were investigated in a serial study and compared with a normal control group. The means of all BTG determinations in the MI (34, ± SD = 21-57) and CI (33, ± SD = 19-57) groups were significantly higher than those in the NCCP group (24, ± SD = 17-34; p Ã0.01) and normal subjects (22,5, ± SD = 14-37; p Ã0.001). There was no difference in BTG between those with MI or CI, nor between the NCCP group and normal subjects. Raised numbers of circulating platelet aggregates could not be detected in either MI or CI. The mean BTG levels in both MI and CI patients were significantly raised, compared to normal subjects, on the first day of admission to hospital and remained so on each of the subsequent nine days. Neither heparin plus warfarin nor sulphinpyrazone had any significant effect in lowering BTG levels. 15/40 patients (37.5%) following MI and CI had repeatedly raised BTG levels throughout the study period, and it is suggested that these patients represent an “at risk” group that may benefit from anti-platelet therapy in secondary prevention studies.
Human Plasminogen Variant Chicago III
Authors: Wohl R C , Summaria L , Chediak J , Rosenfeld S , Robbins K C
Published: July 2018

A new abnormal, variant, plasminogen Chicago III has been isolated from a patient with recurring deep vein thrombosis. Studies on the plasma fibrinolytic system of four family members showed no inheritance pattern. Kinetics of activation parameters of Chicago III plasminogen with different activators showed lowered catalytic rate constants from 159fold with urokinase, to 3fold with light (B) chain ‧ streptokinase complex, to 1.3fold with streptokinase. The Michaelis constants of activation of Chicago III plasminogen were 16fold higher with streptokinase, 6fold higher with light (B) chain ‧ streptokinase complex, and similar with urokinase. Each of the three activators exhibited different interaction characteristics with this variant zymogen, as they did with variant Chicago I and Chicago II plasminogens (previously reported). However, the latter variants were characterized by having normal catalytic rate constants of activation, with higher than normal apparent Michaelis constants of activation. Chicago III plasminogen, as well as Chicago I and II plasminogens, has a homogeneous population of molecules; the interpretation of the kinetic data was possible only in terms of a single population of molecules. The plasmins derived from Chicago I plasminogen, and also Chicago II and Chicago III plasminogens, have 100% active sites with normal amidase parameters. Basically, a single population of normal isoelectric forms were found in the Chicago III plasma, with three minor forms, about 11% of the total.

The kinetic parameters have permitted us to classify the four known plasminogen variants into three different classes. The Class A homozygote (Tochigi) has both an active center defect and a charge mutation difference with normal cleavage of the Arg560-Val peptide bond; the Class B homozygote (Chicago I and Chicago II) has a Km of activation defect with impaired activator binding and normal cleavage of the Arg560-Val peptide bond; and, the Class C homozygote (Chicago III) has both a Km of activation defect with impaired activator binding and a kcat of activation defect, and impaired Arg560-Val peptide bond cleavage.
Effects of Cigarette Smoking on the Ultrastructure of Rat Thoracic Aorta and Its Ability to Produce Prostacyclin
Authors: Pittilo R M , Mackie I J , Rowles P M , Machin S J , Woolf N
Published: July 2018

Following exposure of rats to graded doses of fresh cigarette smoke, the aortic endothelium examined by scanning electron microscopy regularly showed alterations. These essentially consisted of areas of blebbing and microvillus-like projections from the luminal surface, and the presence in the majority of cases, of micro-thrombi in the low shear areas just proximal to intercostal branches. Aortas from rats exposed to smoke showed a reduction in prostacyclin production in vitro and platelets from these animals aggregated more readily than did those of controls.
Side Effects of Thrombolytic Treatment with Porcine Plasmin and Low Dose Streptokinase
Authors: Marbet G A , Eichlisberger R , Duckert F , Ritz R , da Silva M A , Biland L , Widmer L K , Schmitt H E
Published: July 2018

In the sequential thrombolytic therapy with porcine plasmin and low dose streptokinase side effects are mainly due to bleeding, intolerance reactions are less important. Treatment had to be prematurely stopped in 42 (37%) of 114 DVT cases because of severe bleeding and in 12 (10%) due to intolerance reactions. The corresponding figures for the 45 cases with arterial occlusions are 15 (33%) and 2 (4%) respectively. The intensity of systemic proteolysis as represented by the thromboplastin time is significantly correlated with haemorrhagic manifestations. Macrohaematuria and bleeding from puncture sites are the most frequent haemorrhagic complications followed by spontaneous bleeding into skin and muscles. Non-fatal intracranial bleeding occurred in 1 DVT case (0.9%) and in 2 patients with arterial occlusions (4.4%). The benefit of this potent thrombolytic regimen would greatly improve if a strong reduction of premature treatment stop could be achieved.
Functional Fractionation of Platelets: Aggregation Kinetics and Glycoprotein Labeling of Differing Platelet Populations
Authors: Haver V M , Gear A R L
Published: July 2018

Platelet heterogeneity has been studied with a technique called functional fractionation which employs gentle centrifugation to yield subpopulations (“reactive” and “less-reactive” platelets) after exposure to small doses of aggregating agent. Aggregation kinetics of the different platelet populations were investigated by quenched-flow aggregometry. The large, “reactive” platelets were more sensitive to ADP (Ka = 1.74 μM) than the smaller “less-reactive” platelets (Ka = 4.08 μM). However, their maximal rate of aggregation (Vmax, % of platelets aggregating per sec) of 23.3 was significantly lower than the “less-reactive” platelets (Vmax = 34.7). The “reactive” platelets had a 2.2 fold higher level of cyclic AMP.

Platelet glycoproteins were labeled using the neuraminidase-galactose oxidase – [H3]-NaBH4 technique. When platelets were labeled after reversible aggregation, the “reactive” platelets showed a two-fold decrease in labeling efficiency (versus control platelets). However, examination of whole cells or membrane preparations from reversibly aggregated platelets revealed no significant difference in Coomassie or PAS (Schiff) staining.

These results suggest that the large, “reactive” platelets are more sensitive to ADP but are not hyperaggregable in a kinetic sense. Reversible aggregation may cause a re-orientation of membrane glycoproteins that is apparently not characterized by a major loss of glycoprotein material.
Diagnosis of Heterozygotes in Glanzmann’s Thrombasthenia
Authors: Stormorken H , Gogstad G O , Solum N O , Pande H
Published: July 2018

A study of a family with a propositus suffering from classical thrombasthenia type I has shown that the new immunochemical methods detect heterozygotes with high reliability. There was no overlapping between heterozygotes and normals, and the concentration of the glycoprotein IIb-IIIa-complex is remarkably constant around 50–60% in the heterozygotes. Furthermore, heterozygotes as a group show an increased bleeding tendency.
Esterification of the Carboxyl Groups in Fibrinogen by the Application of a Highly Specific Methylating Agent
Authors: Osbahr A J
Published: July 2018

The trimethyl oxonium ion specifically modified the free carboxyl groups of fibrinogen. This esterification process resulted in the polymerization of the modified fibrinogen molecule with the production of a polymeric material that resembled the physiologically formed fibrin clot. The extent of methylation of fibrinogen was evaluated by methoxyl determination at each step of the polymerization process. The modified fibrinogen polymerized in approximately ten min with a minimum number of methyl groups being incorporated into the fibrinogen molecule. In this manner, it was shown that modification of carboxyl groups in the fibrinogen by a group-specific methylating agent results in polymerization of the fibrinogen.

The sites of methylation were ascertained by chromatographic analysis which resulted in the identification of β-methyl aspartic acid and γ-methyl glutamic acid derivatives of the fibrinogen. The analytical methods applied were not able to detect the methylation of any additional amino acid residues in the polymerized-methylated fibrinogen. Based on this experimental data, it was formulated that the methylation of fibrinogen involved the esterification of the carboxyl groups of aspartic and glutamic acid with the resultant reduction of negative repulsion between the fibrinogen molecules and thereby culminated in the polymerization of the modified fibrinogen.
Effect of Vitamin E on Endotoxin-Induced Disseminated Intravascular Coagulation in Rats
Authors: Yoshikawa T , Furukawa Y , Murakami M , Watanabe K , Kondo M
Published: July 2018

Experimental disseminated intravascular coagulation (DIC) can be induced by 4 hr sustained infusion of endotoxin in a dose of 100 mg/kg in rats. The experimental model of DIC in rats was used to study the preventive effect of vitamin E, α-tocopheryl acetate, against DIC. Before the infusion of endotoxin, 0.01, 0.1, 1.0 or 10.0 mg/kg/day of α-tocopheryl acetate was injected intraperitoneally for 4 successive days. The preventive effect against DIC was noted in all the parameters, such as fibrinogen and fibrin degradation products, fibrinogen level, prothrombin time, partial thromboplastin time, platelet count, and the number of renal glomeruli with fibrin thrombi, in rats treated with 1.0 or 10.0 mg/kg of α-tocopheryl acetate. From these results, it was shown that vitamin E, α-tocopheryl acetate, inhibited endotoxin-induced experimental DIC in rats.
Acquired Factor XI Deficiency in Systemic Lupus erythematosus
Authors: Vercellotti G M , Mosher D F
Published: July 2018

A variety of coagulation abnormalities has been described in systemic lupus erythematosus (SLE). We report a unique SLE patient with an acquired factor XI deficiency. The low factor XI levels were not due to a classical coagulation inhibitor, but to a plasma factor (probably an immunoglobulin) that selectively bound factor XI. The factor XI deficiency improved after treatment with corticosteroids. Thus it is possible that in SLE immune complexes may bind clotting factors making them unavailable for use in the coagulation cascade.
Enhanced Affinity for Arachidonic Acid in Platelet-Rich Plasma from Rats with Adriamycin-Induced Nephrotic Syndrome
Authors: Delaini F , Poggi A , Donati M B
Published: July 2018

We have measured the response to arachidonic acid (AA) in platelet-rich plasma (PRP) of rats with Adriamycin-induced nephrotic syndrome. For this purpose we measured the kinetics of generation of malondialdehyde (MDA), a stable product of cyclooxygenase activity, in response to platelet stimulation with different concentrations of the substrate. The apparent Km of platelet cyclo-oxygenase for AA was similar in PRP from control rats and rats treated 1–5 days previously, whereas it was significantly reduced, as compared to controls, in PRP of rats treated 2–5 weeks previously. Such a difference was not observed when washed platelet suspensions were tested instead of PRP. Experiments with crossed platelet/plasma systems indicated that in rats treated from 2–5 weeks, a plasmatic abnormality was indeed responsible for the increased affinity of platelets for AA.

It is conceivable that in this nephrotic syndrome model characterized by heavy proteinuria, some plasmatic component would be lost with the urine which is normally modulating the platelet response to AA. The observed increase in platelet affinity for AA could at least partially contribute to the enhanced thrombotic tendency reported in the same experimental model.
A Simple, Sensitive Spectrophotometric Assay for Extrinsic (Tissue-Type) Plasminogen Activator Applicable to Measurements in Plasma
Authors: Verheijen J H , Mullaart E , Chang G T G , Kluft C , Wijngaards G
Published: July 2018

An indirect spectrophotometric assay for extrinsic plasminogen activator has been devised, which is based on the parabolic assay of Drapier et al. (5). The system contains activator, plasminogen, the synthetic plasmin substrate H-D-Val-Leu-Lys-pNA (S-2251, Kabi) and a mixture of soluble fibrinogen fragments prepared by treatment of fibrinogen with cyanogen bromide. The addition of these fibrinogen fragments considerably enhances the sensitivity and specificity of the method owing to specific stimulation of the plasminogen activation by extrinsic plasminogen activator.

The assay conditions were optimized and the application for extrinsic plasminogen activator measurements in plasma euglobulin fractions is demonstrated.
Impairment of Platelet Aggregation by Echis colorata Venom Mediated by L-Amino Acid Oxidase or H2O2
Authors: Nathan I , Dvilansky A , Yirmiyahu T , Aharon M , Livne A
Published: July 2018

Echis colorata bites cause impairment of platelet aggregation and hemostatic disorders. The mechanism by which the snake venom inhibits platelet aggregation was studied. Upon fractionation, aggregation impairment activity and L-amino acid oxidase activity were similarly separated from the crude venom, unlike other venom enzymes. Preparations of L-amino acid oxidase from E.colorata and from Crotalus adamanteus replaced effectively the crude E.colorata venom in impairment of platelet aggregation. Furthermore, different treatments known to inhibit L-amino acid oxidase reduced in parallel the oxidase activity and the impairment potency of both the venom and the enzyme preparation. H2O2 mimicked characteristically the impairment effects of L-amino acid oxidase and the venom. Catalase completely abolished the impairment effects of the enzyme and the venom. It is concluded that hydrogen peroxide formed by the venom L-amino acid oxidase plays a role in affecting platelet aggregation and thus could contribute to the extended bleeding typical to persons bitten by E.colorata.
Tests for Platelet Changes, Acute Phase Reactants and Serum Lipids in Diabetes mellitus and Peripheral Vascular Disease
Authors: van Oost B A , Veldhuyzen B F E , van Houwelingen H C , Timmermans A P M , Sixma J J
Published: July 2018

Platelets tests, acute phase reactants and serum lipids were measured in patients with diabetes mellitus and patients with peripheral vascular disease. Patients frequently had abnormal platelet tests and significantly increased acute phase reactants and serum lipids, compared to young healthy control subjects. These differences were compared with multidiscriminant analysis. Patients could be separated in part from the control subjects with variables derived from the measurement of acute phase proteins and serum lipids. Platelet test results improved the separation between diabetics and control subjects, but not between patients with peripheral vascular disease and control subjects. Diabetic patients with severe retinopathy frequently had evidence of platelet activation. They also had increased acute phase reactants and serum lipids compared to diabetics with absent or nonproliferative retinopathy. In patients with peripheral vascular disease, only the fibrinogen concentration was related to the degree of vessel damage by arteriography.
Arthroscopic Treatment of a Posterior Labral Interposition after a Pediatric Hip Dislocation—A Case Report
Authors: Kruppa Christiane , Dudda Marcel , Schildhauer Thomas , Seybold Dominik
Published: July 2018

We report the case of a 13-year-old boy, who suffered a posterior hip dislocation from playing soccer. Closed reduction was performed urgently. Because of a nonconcentric hip after closed reduction, further imaging was done. An intra-articular bony fragment was identified. Arthroscopic treatment was performed. Through an anterior portal we were able to locate the intra-articular bony fragment, which was located within the region of the fovea. After lifting of the caudal enfolded labral complex, we were able to remove the fragment. Evidence of a grade 3 cartilage defect was present at the femoral head. We were able to reduce the enfolded posterior labral complex, which was stable afterwards without the necessity of additional suture fixations. The concentric hip reduction was confirmed on an anteroposterior view of the hip postoperatively. The patient was instructed to toe tip weight-bearing for 6 weeks with limited range of motion to 60° of hip flexion. Eight weeks after surgery, he was free of pain and discomforts. From our experience, the arthroscopic intervention after pediatric hip dislocation associated with intra-articular bony fragments or posterior labral complex injuries, represents to be a preferred minimally invasive method in contrast to open surgical procedures.
A Computer Assisted Method to Obtain the Prothrombin Activation Velocity in Whole Plasma Independent of Thrombin Decay Processes
Authors: Hemker H C , Willems G M , Béguin S
Published: July 2018

A method is described that, on the basis of the time course of amidolytic activity after the triggering of thrombin generation in normal plasma, allows the calculation of the velocity of prothrombin conversion independent of thrombin inactivating processes.

It is shown how the reaction constants for the α2M-dependent and the α2M-independent thrombin inactivation processes can be obtained in a sample of whole plasma.

The method is verified by demonstrating that the experimentally observed time courses of residual prothrombin and of α2M-thrombin complex coincide with those calculated from the time course of amidolytic activity, and by showing that the course of prothrombin conversion in plasma without α2-macroglobulin or AT III is adequately described if the α2M or AT Ill-dependent breakdown constants are taken zero in the calculations.

It appears that the inactivation of thrombin, endogenously generated in whole plasma, is about half as fast as that of exogenous thrombin added to the plasma.

A computer program is presented that carries out the relevant calculations.
Homozygous Variant of Antithrombin III : AT III Fontainebleau
Authors: Boyer C , Wolf M , Vedrenne J , Meyer D , Larrieu M J
Published: July 2018

A qualitative defect of antithrombin III (AT III) was demonstrated in four members of a large Tunisian family by the discrepancy between a normal amount of antigen and decreased or absent heparin cofactor activity. The propositus, a 3-year-old girl, died from massive intracardiac thrombosis despite oral anticoagulant therapy. Heparin cofactor activity measured in the presence of thrombin or F. Xa was undetectable in her plasma. Anti-F. Xa activity was also absent when using low molecular weight heparin or a synthetic pentasaccharide, representing the binding site to AT III. The lack of affinity of the propositus AT III for heparin was demonstrated by two-dimensional immunoelectrophoresis and chromatography on heparin-Sepha-rose. The parents, first cousins, and the sister of the propositus also demonstrated a qualitative abnormality of AT III, with levels of heparin cofactor activity close to 50% of the normal range. Our data support the view that the abnormal protein was present at the heterozygous state in the parents and sister and at the homozygous state in the propositus. None of the affected family members had thrombotic episodes, except for the propositus. The name of AT III Fontainebleau is proposed for this variant.