bluuebunny/crossref_metadata_2025 huggingface dataset:
The Association of Platelet and Red Cell Count with Platelet Impedance Changes in Whole Blood and Light-Scattering Changes in Platelet Rich Plasma: Evidence from the Caerphilly Collaborative Heart Disease Study
Authors: Sharp Dan S , Beswick Andrew D , O'Brien John R , Renaud Serge , Yarnell John W G , Elwood Peter C
Published: July 2018

This epidemiological study was undertaken to explore possible relationships among various haematological indices, prevalent ischaemic heart disease and platelet “function” as measured by two rather different methods. ADP-induced platelet impedance changes in whole blood were strongly associated with prevalent ischaemic heart disease in a general population of 49-66 year men at increased risk. Adenosine diphosphate (ADP) induced platelet aggregation in platelet rich plasma (PRP) at a constant platelet count and also the whole blood platelet count and red cell (RBC) count were strongly and independently related to ADP-induced platelet impedance changes. Both platelet count and platelet aggregation in PRP assessed by changes in optical density were directly related to increasing platelet “sensitivity” as measured by impedance changes in whole blood but RBC count was inversely related. Positive independent relationships between platelet impedance changes and plasma viscosity and fibrinogen were markedly attenuated when platelet count was taken into account, but this finding does not discount a role for these factors in platelet aggregation. No relationship was noted between white blood cell (WBC) count and platelet impedance changes; however, a significant inverse relationship was noted with platelet aggregation in PRP. These findings indicate that laboratory-based experimental findings can be observed in population based studies, and that these haematological factors may be important indicators of ischaemic disease in the population.
Effect of Peptides on the Inactivation of Tissue Plasminogen Activator by Plasminogen Activator Inhibitor-1 and on the Binding of Tissue Plasminogen Activator to Endothelial Cells
Authors: Wittwer A J , Sanzo M A
Published: July 2018

The effectiveness of tissue plasminogen activator (tPA) in thrombolytic therapy is dependent upon the rate at which therapeutically administered tPA reaches the clot site and the proportion of that tPA which is enzymatically active. Interactions between tPA and its main plasma inhibitor (PAI-1) and between tPA and the endothelial cells lining blood vessels are two factors which may limit efficacy. In an attempt to identify the regions of the tPA molecule involved in these interactions, we have examined a series of synthetic peptides with amino acid sequences corresponding to different regions of the tPA molecule for their ability to protect tPA from inactivation by PAI-1 and for their ability to reduce the binding of tPA to endothelial cells. Three peptides were identified which were especially effective at maintaining tPA activity in the presence of PAI-1 and three others were found which had a lesser effect. These same peptides were also found to inhibit the binding of tPA to endothelial cells. This suggests that the same regions of the tPA molecule are involved in both processes. None of the peptides inhibited the binding of tPA to fibrin. These peptides may serve as models for the development of agents for enhancing the activity of both endogenous tPA and of tPA administered in thrombolytic therapy.
Low Incidence of Antibodies to Recombinant Human Tissue-Type Plasminogen Activator in Treated Patients
Authors: Reed B R , Chen A B , Tanswell P , Prince W S , Wert R M , Glaesle-Schwarz L , Grossbard E B
Published: July 2018

Sera from over 1,600 patients who received recombinant human tissue plasminogen activator (rt-PA) during clinical trials were assessed for the presence of antibodies to this therapeutic agent. The rt-PA was administered by a variety of dosage regimens for several different indications. Two different forms of rt-PA were used; one was a predominantly two chain form, and the other was a predominantly one chain form. A sensitive radioimmunoprecipitation assay was used to measure antibodies to rt-PA in patients’ serum before and after treatment. Of 932 patients tested with this assay, 929 were negative for antibodies to t-PA. Three patients developed low titers after treatment. Additional serum samples were obtained from these three patients within 2 years after rt-PA therapy and were negative for antibodies to t-PA. With the limited number of positive samples, no correlation could be found with dose or type of rt-PA, dosing regimen or clinical diagnosis. The virtual absence of antibody formation was confirmed in an additional 754 patients using a novel competitive two-site ELISA. It can be concluded that a single infusion of rt-PA was virtually unassociated with antibody formation, suggesting that repeat treatments could be given when necessary without the risk of immunologic complications as are seen with streptokinase or its derivatives.
Venostasis but not DDAVP Infusion Provokes the Plasma Fibronectin Increase
Authors: Letowska M , Bykowska K , Sablinski J , Lopaciuk S , Kopeć M
Published: July 2018

Plasma fibronectin (pFN), von Willebrand factor antigen (vWf: Ag), factor VIII procoagulant activity, fibrinogen, euglobulin lysis time (ELT) and hematocrit were determined in healthy blood donors before and after venostasis as well as after intravenous infusion of l-deamino-8-D-arginine vasopressin (DDAVP). Both venostasis and DDAVP provoked an increase in vWf : Ag and shortening in the ELT. In contrast, venostasis only but not DDAVP induced an increase in pFN levels which was statistically significant with and without correction for a concomitant hematocrit increment. The results indicate that there is a distinct difference in the patterns of venostasis and DDAVP mediated release of proteins from the vessel wall.
Von Willebrand Factor Antigen Is Less Sensitive than Ristocetin Cofactor for the Diagnosis of Type I von Willebrand Disease -Results Based on an Epidemiological Investigation
Authors: Rodeghiero Francesco , Castaman Giancarlo , Tosetto Alberto
Published: July 2018

Recently, in an epidemiological investigation involving 1,218 children aged 11-14, we demonstrated that the prevalence of von Willebrand’s disease, based on a low ristocetin cofactor activity (RiCof) in children with a personal and/or family history of hemorrhage, was at least 1% (Blood 1987; 69: 454). All the diagnosed cases had multimeric patterns typical of type I von Willebrand’s disease (vWd). Since standardization of RiCof is difficult and the test is not easily performed in a clinical laboratory, we measured von Willebrand factor antigen (vWf: Ag) in all available unthawed plasma samples of previously investigated children by ELISA, to assess the relative sensitivity of this more simple test for diagnosing vWd.

Separate normal ranges were calculated by non-parametric methods for 0 and non-0 subjects, and for children and adults, since values were higher in non-0 subjects and in children.

Taking into account the 90% confidence interval around the lower limit of the normal range, 7 (50%) of the 14 cases diagnosed by RiCof were detected by vWf: Ag. Furthermore, two new cases would have been diagnosed by vWf: Ag, leading to a relative Ag/ RiCof global sensitivity of 64%. A similar figure was obtained when the two tests were compared in the group of relatives of the affected children.

In conclusion, measurement of vWf: Ag seems to be definitely less sensitive than the RiCof assay for detecting patients with vWd, even in type I patients, and RiCof remains the test of choice for screening for vWd in hemorrhagic patients.
Effect of Soluble and Immobilized Plasmin on Fibrinogen and Platelets
Authors: Senatore F , Shankar H , Ho C H , Avantsa S , Allon M , Posteraro R
Published: July 2018

Plasmin was immobilized on collageno-elastic tubes (CET) using carbodiimide as the cross-linking agent. The effects of plasmin-CET grafts and corresponding soluble plasmin on fibrinogen, thrombin-mediated fibrinogen activation, and platelet activity, were investigated

There was a significant increase in fibrinogen deposition on plasmin-CETs over non-plasmin (i.e. control) CETs. Furthermore, exposure of fibrinogen to plasmin CETs enhances its deposition to control grafts situated downstream. Plasmin-bound CETs retained higher platelet deposition when preliminarily coated with fibrinogen. Finally, plasmin exerted a positive effect on thrombin-mediated fibrinogen activation at low plasmin concentrations. A mechanistic hypothesis aimed at interpreting this
finding is proposed.
A Comparison of General Anesthesia and Regional Anesthesia as a Risk Factor for Deep Vein Thrombosis Following Hip Surgery: A Critical Review
Authors: Prins Martin H , Hirsh Jack
Published: July 2018

We evaluated the evidence in support of the suggestion that the risk of deep vein thrombosis after hip surgery is lower with regional than with general anesthesia. A literature search was performed to retrieve all articles which reported on the incidence of postoperative thrombosis in both fractured and elective hip surgery. Articles were included if the method of anesthesia used was reported and if they used mandatory venography. Based upon the quality of study design the level of evidence provided by a study was graded.

In patients who did not receive prophylaxis there were high level studies in elective and fractured hip surgery. All studies showed a statistically significantly lower incidence of postoperative deep vein thrombosis with regional anesthesia (relative risk reductions of 46-55%). There were no direct comparative studies in patients who received prophylaxis. However, between study comparisons did not show even a trend towards to lower incidence of postoperative thrombosis with regional anesthesia.
Two Daily Subcutaneous Injections of Fragmin as Compared with Intravenous Standard Heparin in the Treatment of Deep Venous Thrombosis (DVT)
Authors: Bratt Göran , Åberg Wiveca , Johansson Margareta , Törnebohm Eva , Granqvist Staffan , Lockner Dieter
Published: July 2018

In a prospective, randomized, open study 119 consecutive patients with phlebographically verified deep venous thrombosis (DVT) of the leg (36% distal and 64% proximal) were treated either with a low molecular weight heparin (Fragmin, Kabi-Vitrum) subcutaneously (120 anti-FXa U/kg) twice daily or standard heparin (SH) as continuous intravenous infusion (480 IU kg−1 day−1). The Fragmin doses were adjusted to achieve an anti-FXa activity of 0.2-0.4 U/ml before injection and not greater than 1.5 U/ml 4 h after the morning injection. The SH dose was modified to prolong the APTT 2-3 times.

Repeat phlebography after 5-7 days showed improvement in 34/45 patients (76%) in the Fragmin group and in 30/49 patients (61%) in the SH group and progress in 2/45 (4%) and 3/49 (6%), respectively. The mean Marder scores decreased from 18.7 ± 12.1 to 15.7 ± 12.7 in the Fragmin group and from 16.9 ± 12.0 to 14.4 ± 11.8 in the SH group (ns). Two patients in the SH group and none in the Fragmin group had major bleedings.

After 22 ± 7 months follow up 6 rethromboses had occurred in the SH group and 4 in the Fragmin group. Postthrombotic signs and symptoms were similar in both groups.

We conclude that two daily sc Fragmin doses seem as effective and safe as continuous SH in the treatment of DVT of the leg.
ARIC Hemostasis Study -II. Organizational Plan and Feasibility Study
Authors: Wu K K , Papp A C , Patsch W , Rock R , Eckfeldt J , Sharrett R
Published: July 2018

In our previous paper, we reported the development of a blood collection and processing system (BCPS) suitable for the ARIC multicenter hemostasis study. As an additional step of preparation for the ARIC study, we incorporated this BCPS into an organizational plan to increase efficiency and minimize errors. We initially designed organizational trays for blood collection tubes and aliquot tubes and developed a coordinated step-by-step plan for the orderly processing of blood samples. Once the plan was considered workable, we carried out a pilot study to test the feasibility of this integrated organizational plan. Included in the pilot study were 95 healthy subjects randomly selected from 4 ARIC field centers, whose age and gender were comparable to those projected for the ARIC population. We determined the time lapse of filling the first tube as an index of blood flow. The overall mean time-lapse was 23 s (S.D. = 5). There was no significant difference among the field centers. We also determined the entire time lapse required for completing the sample processing. The total processing time was always less than 60 min. By performing the processing of samples in pairs, all the samples from two subjects could be completely processed in 70 min. This greatly increased the efficiency of field center operation. We evaluated the potential in vitro hemostasis activation by measuring plasma Β-thromboglobulin and platelet factor 4 levels. The geometric means of both proteins were comparable to our previously reported results. Fibrinogen, factor VII, factor VIII, von Willebrand factor, antithrombin III, protein C and activated partial thromboplastin time were analyzed. All the hemostatic measurements exhibited no shift of the values. We conclude that the organizational plan together with the BCPS facilitate the incorporation of hemostasis measurements into the ARIC study. It should be valuable as a general guide for other multicenter studies measuring hemostatic factors.
Prevention of Reocclusion by MCI-9038, a Thrombin Inhibitor, Following t-PA-lnduced Thrombolysis in a Canine Model of Femoral Arterial Thrombosis
Authors: Mellott Michael J , Connolly Thomas M , York Sally J , Bush Larry R
Published: July 2018

We compared a selective thrombin inhibitor (MCI-9038; Argatroban), a thromboxane A2 (TXA2) receptor antagonist (L-670,596) and a serotonin-2 receptor antagonist (ketanserin) for their ability to hasten clot lysis and delay reocclusion in a canine model of femoral arterial thrombosis. Occlusive thrombosis was induced by insertion of a thrombogenic copper coil. Femoral arterial blood flow velocity (FABFV) was monitored directly and continuously by Doppler flowmetry. Thrombolysis was induced with tissue plasminogen activator (t-PA; 0.8 mg/kg, i.v.), starting 60 min after thrombotic occlusion and continued for 90 min. Ten minutes after occlusion, dogs received an intravenous infusion of either vehicle, MCI-9038 (10 Μ;g kg−1 min−1), ketanserin (0.1 mg/ kg bolus plus 5 pg kg−1 min−1), D670,596 (1 mg/kg bolus plus 17 pg kg−1 min−1) or a combination of D670,596 and ketanserin. All infusions were discontinued 1 h after stopping the t-PA, and were followed by a 30 min observation period. The times to thrombolysis were similar for all treatments (mean ± SEM = 47 ± 3; all groups). MCI-9038 prevented reocclusion, defined as permanent cessation of FABFV during the hour after stopping the t-PA. All dogs receiving MCI-9038 reoccluded within 30 min after stopping its infusion (71 ± 3 min). Reocclusion occurred in all other dogs, except one vehicle-treated dog and a second dog that received L-670,596 plus ketanserin. Vehicle-treated dogs reoccluded within 23 ± 8 min. Reocclusion was not delayed significantly by ketanserin, L-670,596 or the combination of the two. Thus, in this model, MCI-9038 prevented reocclusion, suggesting that thrombin may be an important mediator of arterial rethrombosis after t-PA-induced thrombolysis.
A Comparative Study of Three Methods for the Visualization of von Willebrand Factor (vWF) Multimers
Authors: Ledford M R , Kent J W , Civantos F
Published: July 2018

This study was performed to compare three visualization methods for the detection of vWF multimers: autoradiography (125I), electroblot with a horseradish peroxidase system (BLOT-HRP), and an avidin-biotin peroxidase system (AV-BIO). Each method was evaluated according to: 1) ability to visually detect bands and subbands thereby identifying von Willebrand’s disease (vWD) subtypes and normals, 2) reagent availability, 3) cost, and 4) time requirements. Additionally, resolvability was evaluated utilizing low, intermediate, and high resolution gels prepared with both low and high gelling temperature agaroses with subsequent visualization by the three detecting systems.

With intermediate resolution gels, our results showed that all three visualization methods could discern pathologic patterns from normal. In addition, the avidin-biotin peroxidase system demonstrated the best band discreteness with low resolution gels used to detect unusually high molecular weight multimers. With high resolution gels used for subtyping type II vWD, we found the internal band structure was best demonstrated using LGT agarose and the electroblot horseradish peroxidase system.
Behçet Syndrome Associated with Protein S Deficiency
Authors: Chafa O , Fischer A M , Meriane F , Chellali T , Sternberg C , Otmani F , Benabadji M
Published: July 2018

Beçget syndrome is a multisystem disorder characterized by ocular, mucocutaneous, articular, gastrointestinal and neurologic abnormalities. We report here an unusual case of Beçget syndrome, characterized by the importance of the thrombotic events(7 phlebitis of both legs and resection of two toes). Additional manifestations of the Beçget syndrome occurred only 10 years after the first thrombotic episode. The oldest daugther of the propositus and his brother suffered also from thrombophlebitis; this familial history of thrombosis led to the performance of a haemostatic study. A congenital protein S deficiency was found in the propositus and in three of his children. Normal protein S levels were found in nine unrelated patients with Beçget syndrome. Thus this observation suggests that, when thrombotic manifestations are the first and major symptom of Beçget syndrom, an additional cause of thrombosis has to be investigated.
Production and Therapeutic Use of a Factor XI Concentrate from Plasma
Authors: Bolton-Maggs P H B , Wensley R T , Kernoff P B A , Kasper C K , Winkelman L , Lane R S , Smith J K
Published: July 2018

Factor XI deficiency is an uncommon bleeding disorder usually manifested by excessive bleeding after surgery or trauma. Until recently the only effective therapy has been fresh-frozen plasma (FFP) infusion. We describe the efficacy and safety of a new factor XI concentrate produced from human donor plasma by a modification of the method used for antithrombin III concentrate. The mean recovery of factor XI in the circulation measured on 62 occasions was approximately 91% of the injected dose, and the mean half-disappearance-time was 52 h. The concentrate was used for 31 invasive procedures in 30 patients, including 16 patients who had a definite bleeding tendency on previous occasions, with normal haemostasis being achieved in all but 1. Only 1 patient (previously experiencing allergy to FFP) experienced adverse effects during infusion. Monitoring of liver function tests and viral antibody status in suitable patients has shown no evidence of transmission of hepatitis viruses, HIV-1 or parvovirus B19.

We conclude that this concentrate provides effective treatment for patients with factor XI deficiency. Preliminary results suggest safety from virus transmission, but this needs to be established in further studies of previously untreated patients.
Characterization of Three Alboaggregins Purified from Trimeresurus albolabris Venom
Authors: Peng Manling , Lu Weiqi , Kirby Edward P
Published: July 2018

Alboaggregins (AL-A, AL-B, AL-C) isolated from Trimeresurus albolabris snake venom represent a new family of proteins which bind to platelet glycoprotein lb (GPIb). These alboaggregins were purified to homogeneity with ion exchange HPLC (Mono-Q column) and hydrophobic HPLC (TSK Phenyl-5PW column). On SDS-polyacrylamide gel electrophoresis, apparent molecular weights of AL-A, AL-B and AL-C were 52 kDa, 26 kDa, and 121 kDa respectively, under nonreducing conditions. Upon reduction, each alboaggregin showed two types of chains with apparent molecular weights in the range of 15-20 kDa. All three alboaggregins agglutinated formalin-fixed platelets. Agglutination activities and binding of labeled alboaggregins to GPIb were specifically inhibited by the monoclonal antibody AK2 which is directed against the 45 kDa N-terminal region on GPIb, but not by monoclonal antibodies against other epitopes on GPIb. 125I-alboaggregin binding to platelets was not altered by the presence of thrombin. Alboaggregins did not bind to GPIIb/IIIa. Alboaggregins were competitive inhibitors for 125I-bovine vWF binding to platelets. Mutual competition studies between AL-A, AL-B and AL-C for the binding of labeled bovine vWF and AL-B to platelets demonstrated that AL-B and AL-C had a significantly higher affinity than AL-A.
Low Molecular Weight Heparin Therapy: Is Monitoring Needed?
Authors: Boneu B
Published: July 2018

Recent meta-analyses indicate that low molecular weight heparins (LMWH) are more effective than unfractionated heparin (UH) in preventing and treating deep vein thrombosis. This article presents the arguments for and against the need for laboratory monitoring. At the present time, the only tests currently available for monitoring LMWH therapy are those which measure the anti Xa activity in the plasma. Due to lower binding to plasma proteins and to cell surfaces,the plasma anti Xa activity generated by a given dose of LMWH is more predictable than for UH.

Some clinical trials suggest that LMWH delivered at the recommended dose expose the patient to less bleeding risk than UH. Several . meta-analyses indicate comparable risk while any overdose unaccept-ably increases the haemorrhagic risk. The lowest dose of LMWH still effective in treating established DVT is presently unknown; some reports indicate that inadequate doses of LMWH are associated with a lack of efficacy for prevention. An overview of the published clinical trials indicates that the LMWH dose has never been monitored for prevention of DVT. In the treatment of established DVT, several trials have been performed without any monitoring, while in others the dose was adapted to target a given anti Xa activity. These considerations suggest that in prevention of DVT, monitoring the dose is not required. In the treatment of established DVT, considering the haemorrhagic risk of LMWH, the risk of undertreating the patient and the absence of large clinical trials comparing the advantages of monitoring the dose or not, it might be useful to check anti Xa activity at least once at the beginning of the treatment but the need for this initial check remains to be established. Because a large proportion of patients will be in the desired range, dose adjustments will be far less frequent than for UH.
Thrombin-Hirudin Complex Formation, Thrombin-Antithrombin III Complex Formation, and Thrombin Generation after Intrinsic Activation of Plasma
Authors: Gallistl Siegfried , Muntean Wolfgang
Published: July 2018

To investigate the relative importance of direct inhibition of thrombin by complex formation and of inhibition of thrombin generation to the mechanisms by that unfractionated heparin (UH) and recombinant hirudin (rH) exert their anticoagulant effects, thrombin-antithrombin III complex (TAT) and thrombin-hirudin complex (THC) formation was compared with the generation of thrombin and prothrombin fragments 1 + 2 (F 1 + 2). Clotting was initiated by activation of citrated plasma in the absence or presence of UH or rH using partial thromboplastin, ellagic acid and calcium chloride. THC was determined by means of ELISA using specific antibodies to thrombin and rH.

Activation of citrated plasma resulted in a sudden onset of thrombin generation after a lag phase of 2 min. Addition of 50 ng rH/ml plasma or 0.1 UH/ml plasma prolonged the clotting time to 3 min. While the peak of thrombin was only slightly decreased in hirudinized plasma, in heparinized plasma thrombin generation was significantly lower than in not anticoagulated plasma. This difference was more pronounced when the lag phase was prolonged to 5 min using 400 ng rH/ml plasma or 0.35 U UH/ml plasma. Using 1200 ng rH/ml or 0.65 U UH/ml to obtain a clotting time of 9 min only a small amount of thrombin could be detected in heparinized plasma, but hirudinized plasma still showed a high peak of thrombin. F 1 + 2 showed essentially the same pattern as thrombin. Prior to the onset of visible clot formation in all experiments using different concentrations of UH about the same values of TAT were observed. In contrast, when samples were anticoagulated with different amounts of rH, a dose dependent increase of THC was detected. When calculated from TAT and THC formation, much more thrombin was bound by rH than by AT III.

Our experiments show that after intrinsic activation of plasma UH exerts its anticoagulant effect more by inhibiting thrombin generation, while rH suppresses thrombin generation to a much lesser extent but inhibits clotting more by direct inhibition of thrombin due to the formation of THC.
Structural Alterations in Fibrin Clots with Dextran
Authors: Muzaffar T. Z , Stalker A. L , Bryce W. A. J , Dhall D. P
Published: July 2018

Theoretical reasoning underlying physicochemical measurement of opacity ratio of fibrin clots, i. e. the ratio of turbidity at 350 nm and 608 nm is given. From such considerations it is deduced that opacity ratio may be used to characterise clot morphology : opacity ratio will be inversely related to the size of inhomogeneities formed in the clot.

A highly reproducible technique for the measurement of opacity ratio is described. Additions of small amounts of dextran to fibrinogen solution consistently decrease the opacity ratio of clots made subsequently. This decrease which indicates that the inhomogeneities forming in such fibrin clots are larger than control, is independent of the molecular weight of dextran, but is related to the logarithm of the final dextran concentration. Both thrombin and fibrinogen concentrations are also determinants of opacity ratio. Electron microscopy of fibrin clots made in the presence of dextran confirms that such clots have an altered morphology. Properties of clots in relationship to their structural morphology are discussed.
Studies on Activator Formation in Human Plasma with Streptokinase
Authors: Martin M ,   with the technical assistance of Frau R. Albrecht and Frau M. Altmaier
Published: July 2018

The plasminogen-streptokinase complex called “activator” was present in diluted plasma in the form of a largely dissociated mixture. More than ⅞ of the streptokinase and plasminogen molecules were available for further activator formation.

The activator is probably a dissociated complex of the formula

Streptokinase + Plasminogen ⇄ Activator.

The fact that an increase in activator concentration by x times is obtained by multiplying either the streptokinase content by the factor y or the plasminogen concentration by the same factor y would point to a kinetic effect along the lines of the mass action law.
A Controlled Trial of Aspirin in Childhood Glomerular Disorders
Authors: Trygstad Carl W. , Bang Nils U. , Heldenreich Robert O. , Csiscko Barbara M. , Rodda Bruce
Published: July 2018

A controlled, prospective, double-blind study of the effect of aspirin on the clinical course and renal function of 36 children with proliferative glomerulonephritis or the nephrotic syndrome was undertaken. Despite unequivocal evidence of suppression of platelet aggregation with aspirin treatment, there were no statistically significant changes in the clinical course or any of the laboratory parameters denoting activity of the chronic glomerular renal disorder. It would appear, therefore, that additional factors besides local platelet aggregation must be involved in the perpetuation of chronic childhood renal disease.
Do Coagulation Screening Tests Detect Increased Generation of Thrombin and Plasmin in Sick Newborn Infants?
Authors: Schmidt Barbara , Vegh Patsy , Johnston Marilyn , Andrew Maureen , Weitz Jeffrey
Published: July 2018

Background: Disseminated intravascular coagulation (DIC) is usually diagnosed in sick infants who have prolonged clotting times, depletion of platelets and coagulation factors, and elevated levels of fibrin derivatives. However, the diagnostic accuracy of abnormal coagulation profiles in neonates at risk of DIC has been uncertain. Since DIC is characterized by activation of both the coagulation and fibrinolytic systems, the objective of this study was to determine whether coagulation screening tests correctly identify infants with biochemical evidence of increased thrombin and plasmin generation.

Methods: Non-surgical patients in a tertiary care nursery who were sick enough to require an indwelling arterial catheter for monitoring purposes, were enrolled in a prospective cohort study. Blood samples for thrombin/antithrombin III (TAT) complexes and the plasmin-derived fibrinopeptide Bβ1-42 were drawn 36 to 72 h after birth from a free-flowing arterial line. Platelet counts, D-Dimer levels, plasma fibrinogen concentrations and prothrombin times, expressed as International Normalized Ratios or INR, were measured at the same time.

Results: One hundred patients were studied. Fifty-seven infants had elevated levels of TAT (≥4 μg/l) and Bβ1-42 (≥4 nmol/l). The sensitivities of platelets <150 × 109/l, D-Dimer >500 ng/ml, fibrinogen <1.5 g/l, and INR >1.5 were 39%, 30%, 12%, and 11%, respectively. Corresponding specificities were 88%, 91%, 98%, and 95%.

Conclusions: Abnormal coagulation screens in sick newborn infants strongly support a diagnosis of DIC. However, normal screens do not exclude activation of the coagulation and fibrinolytic systems.
Activation of Protein C and Its Distribution between Its Inhibitors, Protein C Inhibitor, α1-Antitrypsin and α2-Macroglobulin, in Patients with Disseminated intravascular Coagulation
Authors: Scully M F , Toh C H , Hoogendoorn H , Manuel R P , Nesheim M E , Solymoss S , Giles A R
Published: July 2018

Activation and inactivation of protein C during the clinical course of disseminated intravascular coagulation (DIC) was studied in three patients by qualitative (Western blotting) and quantitative (ELISA) analysis and the intensity of procoagulant activity monitored by the measurement of thrombin and factor Xa antithrombin III complexes. In one patient, inhibitor complexes of APC with protein C inhibitor (PCI) and α1-antitrypsin (α1-AT) were observed and the latter predominated at presentation. Both disappeared during the development of remission but the loss of α1-AT complexes preceded PCI complexes which on Western blotting appeared to increase in intensity prior to disappearance. The two other patients bled to death from uncontrollable haemorrhage. In both cases, APC/inhibitor complexes with α2-macroglobulin (α2-M) in addition to PCI and αr-AT were detected and persisted until death. Although PCI appeared to be the primary inhibitor in all three cases, α1-antitrypsin and particularly α2-macroglobulin appeared to assume greater roles in the two fatal cases. These data are similar to previous findings in an experimental animal model of DIC that suggested that α2-macroglobulin and α1-antitrypsin become more important inhibitors of APC as the primary inhibitor PCI is consumed in the face of a sustained procoagulant challenge.
Comparative Effects of Enoxaparin and Heparin on Arterial and Venous Clot Lysis with Alteplase in Dogs
Authors: Stassen Jean-Marie , Rapold Hans J , Vanlinthout Ingrid , Collen Désiré
Published: July 2018

The effects of Enoxaparin with a specific anti-thrombin (anti-IIa) activity of 32 U/mg and a specific anti-factor-XA (anti-Xa) activity of 96 U/mg, and of heparin with a specific anti-IIa and anti-Xa activity of 192 U/mg, on thrombolysis with alteplase (Actilyse®) were compared in a randomized blinded study using a combined arterial and venous thrombosis model in the dog. All dogs received an intravenous bolus of 5 mg/kg lysine-acetyl salicylate and 0.5 mg/kg alteplase over 60 min. Twenty-eight dogs were randomly assigned to seven treatment groups: placebo, Enoxaparin 1.5, 3 or 6 mg/kg, or heparin 0.5, 1 or 2 mg/kg, given as a 50% intravenous bolus and a 50% infusion over 2 h. Steady-state plasma levels ranged from 0.37 to 1.0 anti-IIa U/ml and 0.9 to 3.1 anti-Xa U/ml for Enoxaparin and from 0.4 to 2.3 anti-IIa U/ml and 0.42 to 3.2 anti-Xa U/ml for heparin. The activated thromboplastin time with 6 mg/kg Enoxaparin prolonged to 94 ± 19 s and with 2 mg/kg heparin to >150 s.

The time to reflow was 120 ± 36 min with placebo, 19 ± 5 min with 6 mg/kg Enoxaparin (p = 0.03 vs control), and 22 ± 5 min with 2 mg/kg of heparin (p = 0.03 vs control). Arterial patency, expressed in min reflow during the 180 min observation period correlated significantly with the dose of anticoagulant given (r = 0.73, p = 0.003 for Enoxaparin and r = 0.61, p = 0.012 for heparin). When the dose of anticoagulant was expressed in anti-IIa U/kg, Enoxaparin was significantly more potent than heparin (patency times of 0.62 ± 0.15 and 0.21 ± 0.09 min per anti-IIa U/kg respectively, p = 0.04) but in terms of mg/kg or anti-Xa U/kg both anticoagulants were equipotent.

Venous clot lysis also correlated significantly with the dose of anticoagulant given (r = 0.62, p = 0.011 for Enoxaparin and r = 0.76, p = 0.004 for heparin). When the dose of anticoagulant was expressed in anti-IIa U/kg Enoxaparin was equipotent to heparin, but in terms of mg/kg or anti-Xa U/kg heparin was more potent than Enoxaparin (6 ± 2% lysis per mg/kg Enoxaparin and 35 ± 9% lysis per mg/kg heparin, p= 0.001).

In conclusion, Enoxaparin and heparin enhance arterial and venous clot lysis with alteplase differently; for arterial patency, potency correlates with anti-Xa activity whereas for venous clot lysis potency correlates with anti-IIa activity.
Familial High Plasminogen Activator Inhibitor with Hypofibrinolysis, a New Pathophysiologic Cause of Osteonecrosis?
Authors: Glueck C J , Glueck H I , Mieczkowski L , Tracy T , Speirs J , Stroop D
Published: July 2018

In a 29 year old white male with osteonecrosis of both hips and a shoulder, and in his family, we measured basal and stimulated (10 min cuff venous occlusion at 100 mgHg) fibrinolytic activity to determine whether low fibrinolytic activity might be heritable and etiologically associated with osteonecrosis. The proband’s basal tPA-Fx was low, 0.08 IU/ml (normal 0.11-1.94), tPA-Ag was normal (11.6 ng/ml), plasminogen activator inhibitor activity (PAI-Fx) was very high, 119 U/ml (normal 3.5-27), as was his plasminogen activator inhibitor antigen (PAI-Ag), 202 ng/ml (normal 3.2-37.1). The proband’s basal PAI-Fx (119) and PAI-Ag (202) were respectively 6 and 13 standard deviations greater than the mean PAI-Fx (17 ± 15 U/ml) and the mean PAI-Ag (25 ± 13 ng/ml) in 172 concomitantly studied hyperlipidemic men. Alpha-2 antiplasmin, fibrinogen, plasminogen and Lp(a) were normal. Despite lowering TG to 301 mg/dl, basal tPA-Fx remained low, 0.05; PAI-Fx and PAI-Ag remained very high (109 and 191). Following venous occlusion, stimulated tPA-Fx remained very low, 0.1 (normal 2.3-11.3), but tPA-Ag rose normally to 17 (normal 8.4-31.4); stimulated PAI-Fx and PAI-Ag were very high, 134 and 223, (normal PAI-Fx 3.6-24, PAI-Ag 12-96). Stimulated D-dimer was < the 10th percentile, 0.084 μg/ml. With such high PAI-Fx available to bind tPA, occlusionstimulated tPA-Fx could not rise, and fibrinolysis could not be initiated. Neither diseases nor drugs could explain the high PAI-Fx and PAI-Ag, low tPA-Fx, or osteonecrosis. The proband’s father, mother, and sister had very high basal PAI-Ag (240, 69, 66 ng/ml), high basal PAI-Fx (24, 24, 35 U/ml), and normal basal tPA-Fx (0.6, 1.0, and 0.2 IU/ml). Basal PAI-Ag, PAI-Fx, and tPA-Fx were normal in the proband’s son (13, 12, 0.3). The proband’s very high PAI-Fx and PAI-Ag appeared to be inherited, possibly as an autosomal dominant trait, producing hypofibrinolysis. We speculate that his osteonecrosis was caused by familial hypofibrinolysis mediated by high PAI, with subsequent inability to activate fibrinolysis, resulting in inadequate lysis of venous thrombi in bone, impaired bone venous circulation, and venous hypertension of bone characteristic of osteonecrosis.
Human Platelet Antigen 3 (HPA-3): Localization of the Determinant of the Alloantibody Leka (HPA-3a) to the C-Terminus of Platelet Glycoprotein IIb Heavy Chain and Contribution of O-Linked Carbohydrates
Authors: Djaffar Isabelle , Vilette Didier , Pidard Dominique , Wautier Jean-Luc , Rosa Jean-Philippe
Published: July 2018

The human platelet antigen (HPA) 3 system is expressed on GPIIb, one subunit of GPIIb-IIIa, the platelet fibrinogen receptor. It was recently shown that HPA-3 was associated with an Ile843/Ser polymorphism. To investigate further HPA-3 determinant structure, we localized an HPA-3a determinant, recognized by the alloantiserum Leka, within the last 29 amino acids of GPIIbα. This region encompasses the polymorphic Ile843, which, as expected, is substituted into Ser in Leka-negative individuals, as shown by DNA sequence after polymerase chain reaction on platelet RNA. In addition, contribution of glycosylation to the determinant structure was demonstrated since the Leka antigenicity was strongly decreased after specifically removing nonterminal O-linked sugars, but not terminal sialic acids. We have thus refined the localization of an HPA-3a determinant within the last 29 amino acids, including Ile843, of GPIIb heavy chain, and shown that the Leka HPA-3a determinant is dependent, in part, upon the serine-linked carbohydrates adjacent to Ile/Ser843.
Clinical Application Of Urokinase Treated Polymer For Antithrombogenic Medical Material
Authors: Ohshiro T , Kosaki G , Takaqi K
Published: July 2018

Currently, there is an increasing need to develop better medical materials with high antithrom- bogenecity. Attempts have, in fact, been made to improve such materials by the following methods:
1) to develop a material compatible with tissue,
2) to coat a material with protein, 3) to immobilize an anticoagulant agent on the surface of a material, and 4) to immobilize a fibrinolytic enzyme on the surface. Amoung these methods, the last is intriguing.

In this series, we devised the antithrombogenic medical materials for intravenous catheterization, vascular suture and lymph-drainage, based on the fundamental examination. Urokinase was coupled to the surface of polymer by peptide linking. Material was disinfected by EOG.

The results are as follows: 1)This material has 5-10 u. of urokinase activity per cm2. 2)The activity was influenced by the procedure of EOG disinfection. 3)The activity decreased after the repeated fibrinolysis test to 20%. 4) Urokinase treated evatate-tube for intravenous catheterization was used in 26 patients and almost no throbei adhered to tube. 5)Urokinase treated nylon-filament for vessel suture was in 10 patients and two suffered from reocclusion. 6)Urokinase treated nylon-thread for lymph-drainage was in 10 patients and some of them had the effective clinical course. 7) These materials maintained the almost 10% of initial fibrinolytic activity after clinical application.
Hemostatic Defects In Acute Leukemias: Special Investigations Including Agarose-Gel-Filtration Of Plasma Samples
Authors: Asbeck F , Schmitz-Huebner U , Kirchhof B , Zimmermann E , van de Loo J
Published: July 2018

22 patients with acute leukemias were investigated before and during cytostatic polychemotherapy. The mean decrease of peripheral leukocytes was 38 000/mm3 within the first 3 days of treatment. The bleeding tendency could be attributed to thrombocytopenia and one or more of the following mechanisms.

1) Only in febrile patients the development of a PIC could be shown: increase of fibrinogen and soluble fibrin; decrease of prothrombin (E.C.-activation, chrom. substrate), F. V, F. VIII, and antithrombin III (chrom. substrate, immunological). In these patients, no consumption of antiplasmin was demonstrable.

2) Non-febrile patients did not develop a PIC during the cytostatic treatment. 3) In some patients an isolated fibrinolysis could be shown already before treatment: increase of soluble fibrin and FDP; marked decrease of fibrinogen, antiplasmin, and F. XIII, which were correlated with the amount of cytoreduction. In these patients, there was no consumption of AT III.

4) Asparaginase produced the well-known defect in protein synthesis. No further influence of either cytostatic therapy or different cytological classifications of the blasts could be demonstrated.
Streptokinase and Urokinase Activation of Human, Chimpanzee and Baboon Plasminogen
Authors: McKee P. A , Lemmon W. B , Hampton J. W
Published: July 2018

Human, chimpanzee and baboon plasminogens, in that order, were found to be decreasingly susceptible to streptokinase (SK) activation. The relative activation of the three primate plasminogens remained the same when species specific fibrin or casein was used as substrate and when the following conditions were varied: 1. SK concentration; 2. plasminogen concentration; and 3. length of incubation of the SK-plasminogen-substrate reaction mixture. Under the same conditions, the three primate plasminogens were readily activated by human urokinase (UK) and no consistent order of activation by UK was observed. Our findings suggest that the site on plasminogen which interacts with SK has undergone changes during evolution whereas the site at which UK activates each of the three plasminogens has changed little. It remains obscure whether the susceptibility of primate plasminogen to SK activation is a specifically selected genetic trait or is simply a laboratory indication of structural changes in the plasminogen molecule that have occurred for other reasons.
Effects of Chemical Compounds upon Current Induced Thrombosis in Rat Mesenteric Vessels
Authors: Aaron R. K , Srinivasan S , Burrowbs B , Sawyer P. N
Published: July 2018

From previous work in our laboratories, there is a large amount of evidence for an electrochemical mechanism of thrombosis. The blood vessel wall and blood cells are negatively charged under normal conditions. Antithrombogenic drugs increase their negative charge densities while thrombogenic drugs have the opposite effect. Injury makes the blood vessel wall less negatively charged or even positively charged. There is a relation between vascular injury currents and thrombosis. In the present study, the effect of certain chemical agents upon in situ thrombosis in rat mesoappendix vessels, produced by an applied electric current of the sign and magnitude of physiological injury currents, is examined. Compounds such as polyquarternary, with basic groups enhance thrombosis while compounds such as heparin with acidic groups inhibit thrombosis.
Effect of Adrenaline on Thrombosthenin
Authors: Levy-Toledano S , Caen J ,   with the technical assistance of Eva Bodevin
Published: July 2018

It has been found that adrenaline protects the two activities of thrombosthenin from inhibition by NEM if added before or with NEM but not if added after.

The α-blockers of epinephrine, phentolamine, abolishes the protective effect of adrenaline when it is added before adrenaline. We find the same results with noradrenaline but not with 5-hydroxytryptamine.

A parallemism exists between the effect of adrenaline on thrombosthenin and clot retraction, but not on platelet aggregation. This shows possibly that the activities of thrombosthenin are directly linked to clot retraction, but in platelet aggregation it seems that thrombosthenin is necessary but not sufficient.
Kombinierter AHG- und PTA-Mangel
Authors: Schulz K , Nowotny P , Schmutzler R , Duckert F
Published: July 2018

Es wird über die Kombination eines Faktor-VIII- und Faktor-XI-Mangels bei einem Patienten mit schwerer Blutungsneigung berichtet. Die Schwierigkeiten der Differentialdiagnose werden aufgezeigt und ähnliche Fälle in der Literatur diskutiert.
Purification of Antihemophilic Factor (Factor VIII) by Amino Acid Precipitation*
Authors: Wagner Robert H , McLester William D , Smith Marion , Brinkhous K. M
Published: July 2018

1. The use of several amino acids, glycine, alpha-aminobutyric acid, alanine, beta-alanine, and gamma-aminobutyric acid, as plasma protein precipitants is described.

2. A specific procedure is detailed for the preparation of canine antihemophilic factor (AHF, Factor VIII) in which glycine, beta-alanine, and gammaaminobutyric acid serve as the protein precipitants.

3. Preliminary results are reported for the precipitation of bovine and human AHF with amino acids.
Preservation of Morphological Integrity and Clot Retraction Activity of Human Platelets After Freezing
Authors: Djerassi Isaac , Roy Albert , Alvarado Jorge ,   With the technical assistence of TERESITA DACEY
Published: July 2018

Human platelets frozen at −195° C (liquid nitrogen) retain their morphological integrity and ability to promote clot retraction when 5% dimethyl-sulfoxide and 5% dextrose are added to the suspending plasma medium. Slow freezing was more effective than direct immersion in the liquid nitrogen. Although similar results may be achieved with dimethylsulfoxide alone with rigidly controlled freezing rates, the addition of sugars may permit freezing under less critical conditions.

Dimethylsulfoxyd und 5% Dextrose dem Plasmamilieu hinzugefügt werden. Das langsame Einfrieren ist effektiver als das direkte Eintauchen in flüssigen Stickstoff. Obschon ähnliche Resultate mit Dimethylsulfoxyd allein unter exakter Kontrolle der Einfrierungsgeschwindig-keit erreicht werden können, erlaubt die Zugabe von Dextrose ein Einfrieren unter weniger kritischen Bedingungen.
Nouvelles recherches sur l’accolement des plaquettes aux fibres de collagène
Authors: Hugues J , Lapiere Ch M
Published: July 2018

Ce travail a été entrepris dans le but de préciser les modalités de l’accolement des plaquettes sanguines aux structures conjonctives et d’étudier le rôle de ce phénomène dans l’hémostase et dans la thrombose.

Mieux que les recherches in vivo, les expériences in vitro en microscopie de phase, permettent d’étudier les altérations morphologiques importantes subies par les thrombocytes après leur fixation rapide au collagène purifié précipité sous forme de fibrilles.

Il est démontré que les processus coagulatifs n’interviennent ni dans l’accolement précoce des plaquettes ni dans leur fusion et l’homogénéisation ultérieure de leurs amas. Par contre ces phénomènes sont inhibés, de manière plus ou moins sélective par des antihistaminiques, la réserpine, des antisérotonines, le chlorure mercurique, le fluorure de sodium. Pour beaucoup des produits inhibiteurs il existe un parallélisme entre l’entrave qu’ils apportent à la fixation au collagène des thrombocytes et leur action sur la morphologie de ces éléments.

Le rôle de l’A.D.P., de l’histamine, de la sérotonine dans les phénomènes étudiés, est discuté.

Le recours à divers enzymes tend à prouver que c’est bien le collagène et non d’autres protéines qui intervient dans l’accolement des thrombocytes aux structures conjonctives. On signale que cette propriété de fixation dévolue au collagène ne se limite pas aux seules plaquettes sanguines mais peut s’exercer également sur d’autres corpuscules.

L’étude microscopique in vitro et in vivo de l’accolement des plaquettes aux structures péri vasculaires et de leur agrégation réciproque nous autorise à élaborer un schéma des différents stades, contemporains ou successifs, de l’élaboration du clou hémostatique.

C’est à des perturbations pathologiques de l’une ou l’autre étape de la constitution du clou hémostatique qu’il faut attribuer les saignements prolongés des dyscrasies sanguines ainsi que le suggèrent nos expériences faites avec du plasma riche en plaquettes de patients souffrant de thrombasthénie de Glanz - mann, d’angéio-hémophilie ou d’hémophilie.