Manufacturing of a prothrombin complex concentrate aiming at low thrombogenicity

The paper describes the production of a prothrombin complex concentrate (PCC) with high virus safety and a well-balanced content of vitamin K-dependent clotting factors and inhibitors. Solid-phase extraction is followed in a second step by optimized anion exchange chromatography using a radial column. A step for virus removal by nanofiltration is introduced in addition to the solvent/detergent step. By speeding up the chromatographic step, the period of time required for production is reduced considerably. The activities of the four vitamin K-dependent clotting factors II, VII, IX and X are in ratios of about 1:1:1:1. Protein C, Protein S, and Protein Z are also present in therapeutically effective concentrations. The product shows no thrombogenicity, in either in vivo nor in vitro models. Clinical investigations show that the PCC is a safe and efficient preparation for the substitutive treatment of FIX or FVII in patients suffering from the respective deficiencies. All bleeding episodes have been efficiently controlled with relatively low doses of the concentrate. The surgical procedures have been conducted without any problems in severely FIX and FVIII deficient patients.

In vitro toxicity of surfactants in U937 cells: cell membrane integrity and mitochondrial function

Surface-active agents are components of many drugs and cosmetics. In order to examine their cytotoxic and membrane-toxic potential, various surfactants were examined in U937 cells using the tetrazolium reduction assay EZ4U, a modified XTT test, and the arachidonic acid release test (AART). EZ4U measures the ability of living cells to reduce a colorless tetrazolium salt to an orange water-soluble formazan derivative by mitochondrial dehydrogenases. [3H]arachidonic acid ([3H]AA) is rapidly incorporated into cell membrane phospholipids. Due to membrane disintegration or enzymatic catalysis, it is released into the cell culture medium and can be measured by scintillation technique. The results after 24-hour-exposure are as follow (CC50 microg/ml; RC50 microg/ml): benzalkonium chloride (0.6), Cremophor A25 (1.4; 5.9), sodium cetearyl sulfate (1.6; 19.9), Brij78 (1.6; 7.7), TEGO betaine E (3.0; 19.3), TEGO betaine CKD (4.1; 20.2), TEGO betaine L7 (7.5; 20.0), sodium dodecyl sulfate (7.5; 39.0), Triton X-100 (8.9; 110), polysorbate 80 (48.1; 491), soybean lecithin (7920; 19940).

Pharmacological stimulation of t-PA release

The acute release of tissue-type plasminogen activator t-PA from the vascular endothelium is of decisive importance for the prevention of intravascular fibrin deposits. A dose-dependent t-PA release from the isolated perfused vascular preparations may be induced by mediators (platelet-activating factor, bradykinin, histamine) adrenergic and cholinergic transmitters (isoprenaline, acetylcholine), thrombin, heparin and analogues, and 1-desamino-8-D-arginine-vasopression (DDAVP). Most of the compounds were shown to enhance the t-PA activity also in animal experiments (rats, rabbits, mini pigs). The pharmacologic stimulation of the t-PA release may be convenient for short-term thrombosis, prophylaxis and partial thrombolysis. Presently, this could only be achieved by unfractionated and low molecular weight heparins which have been shown to release t-PA.

A natural rubber drainage tube with antithrombogenic lumen surface

A drainage tube was made by radiation vulcanization of a high polymeric substance based on natural rubber elastomers. Pentosan polysulphate sodium bound to a carrier substance (synthetic type 4A or 13X zeolite) was incorporated in the drainage tube which was then tested for its anticoagulant properties during perfusion with Tris buffer solution, citrated plasma, and blood, resp. The amount of pentosan polysulphate sodium released from the tube walls during perfusion with human citrated plasma in an open circulatory system was sufficient to exert an anticoagulant effect on the streaming plasma. This effect was corroborated by prolonged thrombin times and by unclottability in case of recalcified plasma samples in thrombelastographic studies. The antithrombogenicity test according to Chandler in a closed circulatory system revealed thrombus formation times (TFT) of more than 24 h (control: TFT = 1-3 min in native blood).

HIV-1 gp120 and NMDA induce protein kinase C translocation differentially in rat primary neuronal cultures

Exposure of rat cortical neurons to the human immunodeficiency virus type 1 (HIV-1) coat protein gp120 in vitro causes a rise in the intracellular Ca2+ level and a subsequent translocation of protein kinase C (PKC) from the cytosol to the membrane. Such a translocation persists for at least 2 h, but only in cultures with media not depleted of endogenous glutamate. Enzymatic degradation of glutamate in the medium by the enzyme glutamate-pyruvate transaminase (GPT) abolishes the long-lasting effect of gp120 on the association state of PKC; under this incubation condition the translocation period is < 1 h. Memantine and the ganglioside GM1 prevent N-methyl D-aspartate receptor-mediated long-term translocation of PKC and gp120-mediated neurotoxicity (in the absence of GPT); they have no effect on short-term translocation of PKC. We suggest that gp120-caused neuronal death involves an indirect sensitization step of the NMDA receptors, which ultimately induces neuronal death.

Characterization of human immunodeficiency virus-1-infected cells of myeloid-monocytic lineage (ML-1, HL-60, THP-1, U-937)

The myeloid-monocytic cells ML-1, HL-60, THP-1, and U-937 were chronically infected (for > 2 years) with the lymphotropic human immunodeficiency virus type 1 (HIV-1) strain HTLV-IIIB. Reinfection experiments revealed that viruses obtained from chronically infected ML-1/HIV-1 and HL-60/HIV-1 cells showed a low infectivity if tested with uninfected ML-1 and HL-60 cells in contrast to virus preparations from chronically infected THP-1/HIV-1 and U-937/HIV-1 with their corresponding uninfected cell lines. Analyses of selected cell surface markers revealed a differential expression of CD4, CD8, CD11c, CD14, CD15, CD20, HLA-DR, and HLA-DQ in non- or chronically infected cells. In chronically infected cells, the steady-state levels for tumor necrosis factor-alpha, interleukin (IL)-1 beta, and granulocyte-macrophage colony-stimulating factor mRNA remained unchanged whereas the one for IL-6 dropped.

Effect of sodium pentosan polysulphate on the thrombogenicity of prothrombin complex concentrates

The addition of pentosan polysulphate sodium (NaPPS) to thrombogenic prothrombin complex concentrates (PCC) dose-dependently reduces or abolishes thrombus formation in rats in the stasis model acc. to Wessler. However, no reduction of thrombogenicity was found in PCC preparations manufactured in the presence of NaPPS.

Influence of hypersulfated lactobionic acid amides on tissue plasminogen activator release

Under our experimental conditions, the sulfated bis-lactobionic acid amide, LW 10079, showed the strongest t-PA-releasing effect in the isolated perfused pig ear. In rats the sulfated bis-lactobionic acid amide LW 10121 was the most potent compound in acute t-PA release. In both experiments the bis-lactobionic acid amide LW 10082 did not work as a releaser of t-PA. Therefore in the case of LW 10082, the activation of the fibrinolytic pathway as a possible mechanism of its antithrombotic effect can be excluded.

Toxikologische Aspekte bei der Anwendung von Hirudin

Natives Hirudin und rekombinantes Desulfato-Hirudin wurden bei akuten und subchronischen Toxizitätsstudien in den bisher angewandten Dosisbereichen toleriert. Blutungen als Nebenwirkung traten bei Anwendung antithrombotisch wirksamer Dosierungen nicht auf. Hirudin erwies sich als schwaches Immunogen, so daß bei wiederholter Anwendung therapeutischer Dosen Immunreaktionen nicht zu erwarten sind. Hirudin ließ sich unter In-vivo-Bedingungen antagonisieren bzw. neutralisieren. Die Throm- bogenität von Prothrombinkomplexkonzentraten ließ sich durch Zusatz von Hirudin abschwächen bzw. aufheben. Durch bakterielle Toxine verursachte Hämostasestörungen konnten durch prophylaktische Gabe von Hirudin verhindert werden.

Pharmacological survey of recombinant hirudin

The pharmacological properties of a genetically engineered recombinant hirudin (r-hirudin) were studied in animal experiments. r-Hirudin proved to be a well tolerated substance. I.v. injection of up to 200 mg/kg did not lead to perceptible functional or morphological changes. There were no treatment-related effects on the cardiovascular system of dogs and rats after administration of up to 10 mg/kg. After long-term treatment (4 weeks, 1.0 mg/kg daily), no r-hirudin-related histopathological, haematological or biochemical changes could be found. Formation of antibodies was not detectable. Absorption, distribution, and elimination of r-hirudin were studied in dogs and rats. Pharmacokinetics could be best described by an open two-compartment model with first-order kinetics. After i.v. injection in dogs, r-hirudin is distributed into the extracellular space and eliminated through the kidneys in active form by glomerular filtration. After i.v. administration, a half-life of about 1 h was estimated; s.c. administration prolonged the apparent half-life. Pulmonary absorption was shown. Enteral absorption, placental transfer as well as transfer through the fetal integument were very low. r-Hirudin did not pass the blood-brain barrier. The efficacy of r-hirudin in preventing both venous and arterial thrombosis, vascular shunt occlusion or disseminated intravascular coagulation was demonstrated in rats. Depending on the dose, r-hirudin was able to prevent or reduce stasis-induced venous thrombosis, prolong the patency of an extracorporeal arteriovenous shunt, reduce the incidence of arterial thrombosis caused by vascular wall lesions as well as of microthrombosis induced by thrombin infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Release of plasminogen activator by batroxobin

In the isolated perfused pig ear, batroxobin caused a dose-dependent increase in the release of plasminogen activator. The activator-releasing effect required the presence of the active enzyme. The activator released was of the tissue-type.

Changes of haemostaseological variables in carbon tetrachloride poisoning in rats

On application of carbon tetrachloride to rats disturbances of haemostasis were observed. Antithrombin III and 4-amidinophenylpyruvic acid were found to exert a beneficial action on these disturbances. However, the thrombin inhibitors had no influence on hepatotoxicity and lethality.

Toxicologically relevant disturbances of haemostasis

The normal haemostatic process depends on the normal function of and regular interaction between the vascular wall, the plasmatic coagulation system and the blood platelets. The consequences of interference of chemical compounds with haemostasis are bleeding tendency and bleeding, thrombophilia and thrombosis or disseminated intravascular coagulation. Examples will illustrate that chemicals interfering with haemostasis have different mechanisms and sites of action.

[Pharmacokinetics of 131I-streptokinase]

It has been demonstrated in mouse experiments that 131I-streptokinase undergoes rapid elimination. It has been shown as unfit as a diagnostic agent in the treatment of thromboses.

Characterisation of the vascular plasminogen activator from the pig ear

Spontaneously released plasminogen activator after perfusion with 0.9% NaCl of isolated pig ear was purified by affinity chromatography on Heparin-Sepharose. The molecular weight of the plasminogen activator is about 60,000 Daltons, the isoelectric point lies at pH 7.6. The enzyme is most stable at neutral pH. At 37 degrees C it is stable for two hours. The activator did not show lytic activity either on heated or on PAMBA fibrin plates. The activity of the activator was inhibited by exposure to DFP and PMSF but not by exposure to TLCK and TPCK, suggesting that it is an enzyme with an active-site residue which belongs to the tissue-type activators.

[Effect of phenol ring polymers on the release of plasminogen activators]

The effects of synthetic and natural phenol polymers on the release of plasminogen activator were examined on an isolated vascular preparation of the pig ear. Of the synthetic phenol polymers, the products of caffeine acid and 3,4-dihydroxyphenylacetic acid were found to raise the activity of plasminogen activator. As far as the natural polymers of phenol are concerned, only sodium humate was found to produce an action similar to that of the products of caffeinic acid and 3,4-dihydroxyphenylacetic acid.

Animal experiments on the enhancement of fibrinolytic potential by anabolic steroids

In animal experiments the anabolic steroids 4-chloro-17 beta-hydroxy-17-methylandrosta-1,4-dien-3-one and 4-chloro-11 beta-hydroxy-17-methylandrosta-1,4-dien-3-one were tested for their ability to enhance fibrinolysis in comparison to stanozolol. After daily administration of 2 mg/kg for 12 weeks the anabolic steroids were found to enhance spontaneous fibrinolytic activity of blood, fibrinolytic capacity and tissue plasminogen activator activity in the kidneys of rats and rabbits. Concomitantly, the AT III activity of blood increased.

Chemical control of hyperfibrinolytic states by synthetic inhibitors of fibrinolytic enzymes

The effects of two types of synthetic inhibitor of fibrinolytic enzymes (omega-aminocarboxylic acids, benzamidine derivatives) on intravascular fibrinolysis and fibrinogenolysis were studied in rats. Generalised primary fibrinogenolysis was produced by infusion of human plasminogen-streptokinase complex, secondary fibrinolysis was induced by infusion of the thrombin-like enzyme batroxobin. The inhibitors exerted different effects on the hyperfibrinolytic states. The omega-aminocarboxylic acids (PAMBA, AMCA) inhibited fibrinolysis more effective than fibrinogenolysis. In contrast, the benzamidines (APPA, NANP) were more potent inhibitors of fibrinogenolysis. Aprotinin examined for comparison behaved like the benzamidine derivatives.

[Pharmacokinetic studies with 3H-labelled synthetic antifibrinolytics]

In rabbits and rats pharmacokinetic studies on the anti-fibrinolytics 4-aminomethylbenzoic acid (PAMBA), trans-4-aminomethylcyclohexane-1-carboxylic acid (AMCA), and epsilon-aminocaproic acid (EACA) were carried out using the tritium labelled compounds. Following i. v. administration of PAMBA and EACA in rabbits a two-phasic plasma level and following AMCA a three-phasic plasma level was found within 7 h. The rate constants beta of 0.34 h-1, 0.44 h-1, and 1.08 h-1 for EACA, PAMBA, and AMCA, respectively, indicate a more rapid elimination of AMCA. Accordingly, the AUC-values for AMCA are considerably smaller than those for EACA and PAMBA after both i. v. and p. o. administration.

The use of proteases as thrombolytic agents from the toxicological point of view

In case of systematic hyperproteolysis in the blood of experimental animals after application of ocrase, a fibrinolytically active protease from Aspergillus ochraceus, toxic side effects, particularly on hemostatis and cardiac action, were observed. In order to prevent toxic effects, ocrase in thrombolytic therapy is to be administered within the inhibitor level. After daily administration of 5.6 mg/kg of ocrase (50% of inhibitor level) to rats, toxicological examinations over four weeks showed no deviation from the regular hematological and biochemical values. The thrombolytic effect of ocrase is explained by the formation of an inhibitor-ocrase complex which acts thrombolytically in the presence of fibrin.

Pharmacokinetic studies with 3H-cytisine

The pharmacokinetic behaviour of cytisine was studied in mice by means of tritiated cytisine after intravenous and oral administration of a sublethal dose of 2 mg/kg. After oral administration the maximum blood level is reached after 2 h. The absorption rate is approximately 42%. From the blood level after intravenous administration a half-life of 200 min was calculated. Within 24 h after intravenous administration 32% and after oral administration 18% of the administered radioactivity was excreted into urine. Following intravenous administration 3% of the dose was found in the faeces within 6 h. Among the examined organs and tissues the highest concentrations were reached in the liver, adrenals and kidneys. In the bile the highest concentration after intravenous administration was 200 times that in the blood.

The influence of drugs on the acute toxicity of cytisine

The effect of various drugs on the acute toxicity of cytisine, the toxic constituent of Laburnum anagyroides Med, was studied in mice. Drugs were tested which have been recommended for symptomatic treatment of laburnum poisoning. Drugs which influence the CNS reduce the acute toxicity of cytisine more effectively than those with predominantly peripheral site of action.

[Animal experiments on the pharmacokinetics of ocrase (author's transl)]

The blood level, distribution and elimination of ocrase, a protease from Aspergillus ochraceus, were determined in rabbits after application of the 131I labelled enzyme in therapeutic doses.

[Thrombolytic action of a heparin-ocrase complex]

The thrombolytic action of the complex heparin-ocrase on the experimentally formed fresh thrombi obtained through intravenous introduction of thrombin into an isolated length of the jugular vein was compared against the effect produced on the thrombi by equivalent amounts of individual components of the complex, i.e. heparin and ocrase. Investigations revealed a lysis of experimental fresh thrombi after intravenous injections of the complex heparin-ocrase and this lysis supervened quicker than following the action of equivalent amounts of ocrase. Heparin used in a dose equivalent to its content in the complex did, as this has been presumed, exercise no thrombolytic action at all.