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At least 613 records · Page 34Linked to original sources
PubMed1985

Experimental studies on venous thrombosis: effect of coagulants, procoagulants and vessel contusion.

We have examined the relative contribution of stasis, activated coagulants, procoagulants and vessel wall damage in the pathogenesis of experimental venous thrombosis. Using a Wessler stasis model in rabbits, we found an inverse correlation between duration of stasis and the amount of Contact Factor and Factor Xa required to produce a stasis thrombus. However, the slope of the dose-response curve for producing thrombi was different with these two coagulants. The infusion of Factor IX complex was also thrombogenic in this model despite prolonged circulation prior to stasis, implying that high levels of multiple procoagulants may be thrombogenic. In contrast, Factor VIII concentrates or a purified Factor IX preparation did not give thrombi under these conditions. When the vessel wall was crushed mechanically, followed by restored blood flow and subsequent stasis, there was essentially no formation of thrombi over the time course of the experiments. Scanning electron microscopy demonstrated that although the endothelium was swollen and damaged, there was usually no exposure of sub-endothelium and no adherence platelets. Where there was definite disruption of the endothelium, activated platelets could be seen adhering to the vessel wall. However, the blood in the segments remained fluid over a period of 30 min, despite the presence of adherent platelets. Our experiments demonstrated that the combination of vessel wall damage and stasis was relatively ineffective in producing venous thrombosis. In contrast, high levels of zymogens or small amounts of activated clotting factors, combined with local stasis, is a very effective thrombogenic stimulus in the venous system.

Animals↗
PubMed1985

Comprehensive management of haemophilia.

Haemophilia is a congenital, life-long disorder that may cause major disabilities. The goal of comprehensive care is to prevent problems when possible, to treat early in order to minimize morbidity, and to restore function to disabled patients. The co-ordinated efforts of many experts are needed for success.

Aminocaproic Acid↗
PubMed1981

[Hemostasis disorders after transfusions].

Disturbances of haemostasis caused immunologically and non-immunologically were observed after transfusion of blood and blood derivatives. Transfusion of heparin blood increased the bleeding susceptibility only in case of pre-existing high-degree defects of haemostasis or if they were performed as massive or exchange transfusions. Massive transfusions with blood stored for a long time will induce complex defects. Under intensive substitution therapy of haemophilia A the so-called paradoxical bleeding will occur in spite of a high factor VIII level. These bleedings are supposed to be disturbances of the thrombocyte function and are caused by fibrin(ogen) derivatives. Post-transfusional thrombocytopenias may be brought to remission by repeated plasmapheresis. Factor specific inhibitory bodies will appear after substitution in a small percentage of haemophilic patients. 5 to 7 days after the onset of therapy an anamnestic reaction can be observed as a titre increase by leaps. Usually, the inhibitory titre will decrease to a mostly low basal value in the course of three to five months. The therapy with cyclophosphamide simultaneously started with the substitution will more frequently prevent the anamnestic reaction or reduce it. Titres with more than 5 units cannot be overcome at the beginning even by higher concentrations of preparations. The substitution therapy should be preceded by exchange transfusions or plasmapheresis of up to 25 units. With still higher titres only procedures of inhibitor-bypassing are possible with factor VIII preparations of animal origin or better with activated prothrombin complex preparations, such as FEIBA. Recent reports give evidence that permanent substitution with factor VIII concentrates at a highest dosage can eliminate the production of inhibitors completely.

Blood Coagulation Disorders↗
PubMed1983

The use of factor eight inhibitor by-passing activity (FEIBA immuno) product for treatment of bleeding episodes in hemophiliacs with inhibitors.

FEIBA (factor eight inhibitor by-passing activity) Immuno was used to achieve hemostasis in 46 patients with factor VIII inhibitors with titers greater than 4 Bethesda units, and 3 patients with factor IX inhibitors. One-hundred and sixty-five bleeding episodes were treated with 50-70 U/kg; 102 of these episodes occurred in joints. 20 in mucous membranes, 33 muscle and soft tissue, and 10 were emergency episodes including 3 central nervous system and 4 surgical procedures. Ninety-three percent of the bleeding episodes were controlled, while 7% were not controlled: 36% were controlled by one infusion in 12 hr, another 42% with 1 or more infusions in 36 hrs and an additional 14% were controlled in more than 36 hr. There were no serious side effects, and while the inhibitor titer rose in 10 of the patients, the product continued to be efficacious.

Clinical Trials as Topic↗
PubMed1983

[The problem of factor VIII inhibitors in patients with congenital coagulopathies].

It is reported on a 19-year-old patient with haemophilia A, in whom after a tooth extraction haemorrhages developed which could not be commanded. Factor-VIII-inhibitors could be proved qualitatively and quantitatively. As prospective for the therapy proved to be the administration of activated prothrombin complex preparations (FEIBA). The haemorrhages stopped, the partial thromboplastin time shortened. After three weeks the patient could be dismissed from hospital treatment.

Adult↗
PubMed1983

Autoplex versus proplex: a controlled, double-blind study of effectiveness in acute hemarthroses in hemophiliacs with inhibitors to factor VIII.

In view of uncontrolled observations and anecdotal reports suggesting that the activated PCC, Autoplex, was much more effective than standard (non-activated) PCC in controlling bleeding in hemophiliacs with inhibitors, a controlled double-blind study was designed to compare the effectiveness of Autoplex and Proplex. Acute hemarthrosis was chosen for study as this common but non-life-threatening lesion lends itself well to controlled study. A single dose of "unknown" product (Autoplex 75 FECU/kg; Autoplex 50 FECU/kg; or Proplex 75 FIX U/kg) was given, and effectiveness was judged at 6 hr. By all criteria of efficacy, there were no significant differences between the products. It is noteworthy that a single dose of PCC was judged effective in 50% of episodes, a figure that is consistent with other published clinical trials. In this model, no additional benefit was derived from using the activated PCC, Autoplex, in either dosage.

Blood Coagulation Factors↗
PubMed1984

Incidence of immune responses following 102 infusions of autoplex in 18 hemophilic patients with antibody to factor VIII.

An activated prothrombin complex concentrate (Autoplex) was infused for the treatment of 102 bleeding episodes in 18 hemophilia A patients with antibody to factor VIII who were previously known as high responders. Among 95 bleeding episodes treated with a single infusion of the concentrate [43-107 factor VIII correcting units (FECU)/kg], only 1 anamnestic response was observed. On the contrary, a significant rise in antibody titer occurred following 2 of 4 double (at 8-12 hr interval) and all 3 multiple (over 3-10 days) infusions of Autoplex. The occurrence of immune responses may be explained by the presence of factor VIII coagulant antigen (VIII:CAg) in the 26 batches of Autoplex tested by two-site immunoradiometric assay (10-36 U/vial). The anamnestic response was not correlated to the batch used nor to the amount (0.6-7.8 U/kg/day) of VIII:CAg infused per day. However, exposure to the concentrate over several days appeared to be the major predisposing factor for an immune response.

Adolescent↗
PubMed1984

Approaches to plasma fractionation for improved recovery and the development of potentially useful clinical factors.

World-wide use of large amounts of highly purified Factor VIII and Factor IX concentrates has increased steadily over the last decade. The increase has resulted in more effective treatment of patients with haemophilia, especially those patients on home care and 'demand' therapy, those on prophylactic therapy for chronic bleeding or those on maintenance therapy for the suppression of inhibitors. Changing socioeconomic conditions have also contributed to greater use of the concentrates. The trend is putting an increasing strain on conventional methods for collecting and fractionating plasma. These include the donor, the nature of the anticoagulant, methods for purification of the clotting factors, procedures for denaturation and/or separation of viral contaminants and patterns of clinical usage. As a result, it is essential that we upgrade the quantity and quality of plasma collected and utilize the most effective new methods for increasing the yield and purity of the plasma fractions. Of special significance are recently described procedures for heat inactivation and/or separation of viral contaminants from the fractions and the long-term promise of genetically engineered proteins.

Antibody Formation↗