Bolus application of a novel recombinant plasminogen activator in acute myocardial infarction patients: pharmacokinetics and effects on the hemostatic system.
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Adult↗
Biomedical subjects
E Seifried
Publications and source records attributed to E Seifried.
[Severe tetraparesis as the first manifestation of a chronic lymphatic leukemia].
Uncertain gait and weakness on standing, progressing to flaccid paraparesis of both legs, developed in a 76-year-old woman. Proprioceptor reflexes of both legs were absent and there was pallaesthesia up to the pelvic rim. Electromyography pointed to polyneuritis. Administration of prednisone, 1 mg/kg daily for 10 days, was ineffective, as was one-time plasmapheresis. An incomplete tetraparesis developed. Blood white-cell count increased within 2 weeks by 10,400/microliters (52% lymphocytes) to 17,400/microliters. Blood smear, bone-marrow cytology and histology, as well as immunocytology, revealed lymphoplasmocytoid immunocytomas (chronic lymphocytic leukemia). Oral cytoreductive treatment was started with chlorambucil, 0.1 mg/kg daily, and prednisone, 100 mg daily. After 19 days the patient was able to walk with support, after 28 was walking unaided. Treatment was continued over eight cycles (14 days' treatment, 14 days' interval per cycle). 17 weeks after onset of treatment paraesthesias of the legs required renewed administration of chlorambucil, 0.1 mg/kg per day, for 3 months. The patient has now been free of symptoms during a follow-up period of 12 months.
Aged↗
Thrombotic thrombocytopenic purpura in early pregnancy with maternal and fetal survival.
Thrombotic thrombocytopenic purpura (TTP) is a hematologic disorder which is clinically characterized by thrombocytopenia, microangiopathic hemolytic anemia, fever, neurologic symptoms, and cardiac and renal involvement. The pathogenic mechanisms of this disease are poorly understood. It is well known that TTP is associated with pregnancy and that prognosis for the mother and child is poor. We present the first case of a severe TTP diagnosed in the first trimester of pregnancy (13th week of gestation) with maternal survival and birth of a healthy child which required continuous and intensive treatment with plasma therapy until delivery. During a period of 24 weeks several attempts to discontinue plasma therapy failed because of continuous active disease, and it became evident that plasma infusions were not as effective as plasma exchanges. The fact that the patient entered into remission soon after delivery of a healthy child by cesarean section in the 37th gestational week shows that in this case pregnancy activated an unknown factor which does not cross the placenta and which can be removed by plasmapheresis.
Adult↗
Pharmacokinetics and fibrin specificity of alteplase during accelerated infusions in acute myocardial infarction.
Pharmacokinetics and fibrin specificity of alteplase (recombinant tissue-type plasminogen activator) were determined in 10 patients with acute myocardial infarction undergoing an accelerated infusion regimen during the alteplase/anistreplase patency study (TAPS). Fifteen milligrams of alteplase was administered as an intravenous bolus injection, followed by infusions of 50 mg over 30 min and 35 mg over a further 60 min. Mean steady state plasma concentrations of alteplase during the initial 30 min were 3.2 +/- 0.84 micrograms/ml, measured immunochemically, and 2.1 +/- 0.23 micrograms/ml, measured using a functional activity assay. These values were 45% and 51% higher, respectively, than those during the standard infusion schedule (p less than 0.01). However, the predominant plasma half-life determined by model fitting based on either assay (3.3 to 3.5 min) was unaltered compared with the standard regimen. Maximal concentrations of fibrin and fibrinogen degradation products were 5.1 +/- 2.2 and 1.9 +/- 1.1 micrograms/ml, respectively. Plasminogen decreased to 70% and alpha 2-antiplasmin to 35% of values before infusion. The results indicate that 1) improved coronary patency rates during "front-loaded" infusions can be rationalized in terms of higher plasma concentrations of both free and immunoreactive alteplase, 2) kinetic variables are comparable with those of other dosing strategies, and 3) fibrin specificity is not diminished relative to that of the standard infusion regimen.
Aged↗
[Hemostatic disorders following polytrauma--the role of physiologic coagulation inhibitors during the preclinical phase].
Coagulation changes due to polytrauma are considered to be an important determinant for the outcome. In this context, physiological inhibitors of activated coagulation are highlighted with special reference to antithrombin-III (AT-III). Blood samples of 20 randomly selected adults with polytrauma (Injury Severity Score mean = 36.7 +/- 8.6) were investigated. To investigate the very early onset of coagulation changes, samples were taken as early as possible at the site of emergency (mean = 18.3 +/- 5.5 min. after trauma) as well as at hospital admission (mean = 78.0 +/- 10.4 min.). By means of a specially designed "mini-lab", basic processing of the samples harvested (centrifugation, pipetting, freezing) was done on the spot to obtain haemostaseological results that agree as closely as possible with the subsequent analyses. Due to the activation of intravascular coagulation as well as the consumption of physiological inhibitors, comprehensive coagulation disturbances become obvious at the time of hospital admission. These are intensified by haemodilution as a consequence of high-dose fluid replacement. However, significantly elevated levels of specific coagulation reaction products (thrombin-antithrombin-III-complex) give evidence of the consumption of inhibitory potential exceeding haemodilution.
Adult↗
Studies on the functionality of fibrinogen during rt-PA therapy: results of three different methods of fibrinogen determination.
The conversion of soluble fibrinogen to insoluble fibrin is a crucial event in the process of haemostasis. In the present study three different methods were used for the determination of plasma fibrinogen levels in 12 patients with acute myocardial infarction during rt-PA therapy. Two methods were based on fibrin formation and thus measured 'functional' fibrinogen: a clotting rate assay according to the Clauss method and a photometric polymerization rate assay. Thirdly, fibrinogen antigen was measured with a new enzyme immunoassay (EIA) for immunologically intact fibrinogen. The levels of functional and intact fibrinogen were strikingly different: 4.1 g/l (Clauss) and 3.6 g/l (photometric) vs 2.6 g/l (EIA) at baseline, 2.2 g/l (54% of preinfusion value) and 2.1 g/l (59%) vs 2.1 g/l (81%) at 90 min, 5.7 g/l (146%) and 4.5 g/l (130%) vs 2.7 g/l (106%) at 72 h. The rebound phenomenon exhibited by functional fibrinogen (130-150%) was not observed for levels of intact fibrinogen. A ratio was calculated of functional (Clauss method) to intact fibrinogen (EIA) for each individual patient and each time point. The mean ratio (n = 12 patients) was 1.6 at baseline, 1.0 at 90 min, and increased markedly between 8 and 24 h to a maximum of 2.1 (P less than 0.01). Our data indicate that the 'functionality', i.e. the clotting rate per unit concentration of circulating fibrinogen, changed during acute myocardial infarction and subsequent thrombolytic therapy. This is in keeping with data from literature that the relative amount of fast clotting high molecular weight (HMW) fibrinogen of total fibrinogen was increased in the initial phase of acute myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
Cryopreserved autologous platelet transfusions in alloimmunized patients with acute leukemia.
Autologous platelets of 5 alloimmunized patients with acute leukemia in remission were cryopreserved with 5% dimethylsulfoxide in liquid nitrogen and retransfused in the following therapy-induced thrombocytopenic phase. The mean platelet recovery after freezing, thawing and washing was 85 +/- 6%. The mean corrected 1-hour increment in platelet counts was 11 (4-27) x 10(9)/l, i.e. 61% in comparison with fresh platelet transfusions in other patients. In vivo function of frozen platelets was documented by improvement of the posttransfusion bleeding time. Cryopreserved autologous platelets function hemostatically and can be used even for completely refractory patients and thus permit curative antileukemic therapy.
Adult↗
Thrombolysis using consecutive high dose bolus and infusion of alteplase in a patient with acute massive pulmonary embolism.
We describe the successful use of a novel dosage regimen of alteplase in a 77-year-old man with massive acute pulmonary embolism in the presence of a relative contraindication (recent cranial surgery). An intravenous alteplase bolus of 50 mg was administered, followed 40 min later by a 50 mg infusion over 2 h. Pulmonary arteriography showed a considerable increase in intraluminal filling of thrombotically occluded vessels as a result of alteplase administration, and was accompanied by marked clinical improvement. Peak alteplase plasma concentration after the bolus was 5.5 micrograms/ml, and the steady state concentration during infusion was 0.52 micrograms/ml. Detailed monitoring of haemostasis parameters showed elevated endogenous fibrinolytic activity at baseline, very high levels of fibrin degradation products during treatment resulting from lysis of an extensive thrombus mass, moderate fibrinogenolysis compared to fibrinolysis, long plasma half-lives of fibrin(ogen) degradation products (9.2-11.0 h), and increased thrombin generation. There were no bleeding side-effects. The regimen combines the advantages of rapid onset (bolus) and maintained potency (infusion) of thrombolytic effect in pulmonary embolism.
Aged↗
[Disorders of hemostasis after polytrauma. On the extent of intrinsic fibrinolytic activity in the preclinical phase].
Coagulation disorders are of utmost importance in emergency surgery as well as for secondary organ failure of polytraumatized patients. In order to get hold of the early onset of these disorders, blood samples were harvested from 20 randomly selected patients (Injury Severity Score mean = 36.7 +/- 10.5) on the scene of emergency (mean = 18 [10-29] min after trauma) and at the time of hospital admission (mean = 78 [58-98] min after trauma). In addition to the activation of intravascular coagulation and the consumption of physiological inhibitors, high amounts (10- to 50-fold above normal) of degradation products (FgDP, FbDP, TDP, D-dimers) are present on the scene, already. The influence of hemodilution due to high-volume resuscitation is discussed.
Adolescent↗
[Fibrinolysis and thrombolytic drugs].
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Fibrinolysis↗
[The clinical course of coumarin-induced necrosis].
In three patients painful reddening of a well-circumscribed area of the skin occurred within five days of starting anticoagulant treatment with phenprocoumon (Marcumar), and within a short time it developed into a full-blown picture of coumarin necrosis. The indication for phenprocoumon was, in the first patient (a 29-year-old mother lying-in after her second child had been born) an increased platelet count and the presence of high risk factors for thromboembolism. In the second patient (25-year-old man) and the third one (45-year-old woman) it was secondary prophylaxis after pulmonary embolus and deep-vein thrombosis, respectively. All three patients were very obese and had a drug allergy, as well as other allergies (bronchial asthma in Cases 1 and 2; allergic rhinitis in Case 3). Phenprocoumon was at once discontinued in all three patients and low-dose heparin administration (Cases 1 and 3) or dextran infusion (Case 2: heparin intolerance) started. All three needed excision of the necrotic tissue with grafting to the skin defect. The coexistence of obesity and allergic diathesis may thus present an especially high risk for coumarin necrosis.
Adult↗
[The pathophysiology, clinical picture and treatment of coumarin-induced necrosis].
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Administration, Oral↗
Investigating the presence of HIV sequences and the distribution of virological markers in hemophiliacs and their sexual partners.
In this study, we report the investigation of a hemophiliac cohort, in which the last HIV-1 seroconversion occurred in 1985. We wanted to evaluate whether 5 years later the results of serological screening and polymerase chain reaction (PCR) technology would match. We examined 61 German patients with congenital deficiencies of factors VII, VIII-c, and IX, and 16 sexual partners (15 partners of anti-HIV-1-negative hemophiliacs). Patients' and partners' anti-HIV-1 status was determined by ELISA and Western blot. Further, we applied the PCR to investigate the possible presence of HIV sequences in anti-HIV-1-negative individuals. Four sets of primers were used in four separated reactions to avoid false-negative results due to genetic variation, as well as false-positive results due to DNA carryover. The data by PCR were not different from the data attained by conventional serological methods. The prevalence of serological markers for HBV and HCV was determined.
HIV↗
[Thrombolytic therapy of pulmonary artery embolism in early pregnancy with recombinant tissue-type plasminogen activator].
We report on successful thrombolytic treatment of massive pulmonary embolism in a patient in early pregnancy with recombinant tissue-type plasminogen activator (rt-PA). Therapy was started with 20 mg rt-PA intravenously over 20 minutes, followed by two further infusions of 20 mg rt-PA within the next 8 hours. Clinical symptoms and haemodynamic parameters improved 24 hours after initiation of therapy. No bleeding complications were observed and the foetus was not affected. Further thromboembolic episodes could be prevented by anticoagulation with low molecular weight heparin up to full term normal delivery.
Adult↗
Pharmacokinetics and hepatic catabolism of tissue-type plasminogen activator.
Recombinant tissue-type plasminogen activator (rt-PA, alteplase, Actilyse, Activase; CAS 105857-23-6) is the most effective agent currently available for thrombolytic therapy of life-threatening diseases such as acute myocardial infarction. It acts by rapid, clot-specific lysis of pathological thrombi, with only limited effects on systemic hemostasis. Pharmacokinetics of rt-PA have been extensively characterized in animal species and man, and can be generally described by a 3-compartment model. Preferred analytical methods for rt-PA in plasma are ELISA and chromogenic activity assays. The dominant plasma half-life of rt-PA in myocardial infarction patients is short (3.6 min), which allows excellent control of plasma levels during therapy. Steady-state plasma concentrations effecting coronary thrombolysis using the current dosage regimen are 2.2 micrograms/ml. A deep compartment results in elevated rt-PA concentrations several hours after termination of infusions, which may contribute to short-term maintenance of patency of reperfused blood vessels. Clearance of rt-PA can be saturated in animals at very high plasma concentrations (Km = 12-15 micrograms/ml), however, pharmacokinetics in clinical settings are linear. Clearance occurs via hepatic receptor mediated endocytosis and intracellular degradation in liver parenchymal, endothelial and Kupffer cells. The catabolism involves coated pits, coated vesicles, endosomes, and finally degradation in lysosomes. Current evidence supports the existence of hepatic receptors recognizing carbohydrate as well as polypeptide determinants in rt-PA. In conclusion, increasing knowledge of rt-PA pharmacokinetics will contribute to the optimization of new clinical dosage regimens, such as front-loaded infusions and boluses, and to the identification of novel molecular targets for pharmacologic control of rt-PA catabolism and of circulating fibrinolytic activity.
Animals↗
In vitro effects of urokinase--prevention by different inhibitors.
The present in vitro study investigated dose-, time- and temperature-dependent effects of two-chain urokinase plasminogen activator (u-PA, urokinase) on normal citrated plasma. When 10 micrograms/ml u-PA were added to pooled normal plasma and incubated for 30 min at an ambient temperature (25 degrees C), alpha 2-antiplasmin decreased to 8% of the control value. Incubation on ice yielded a decrease to 45% of control, whereas alpha 2-antiplasmin was fully consumed at 37 degrees C. Fibrinogen and plasminogen fell to 46% and 39%, respectively, after a 30 min incubation at 25 degrees C. Thrombin time prolonged to 190% of control. Various inhibitors were studied with respect to their suitability and efficacy to prevent these in vitro effects. Aprotinin exhibited a good protective effect on fibrinogen at concentrations exceeding 500 KIU/ml plasma. Its use, however, was limited due to interferences with some haemostatic assays. We could demonstrate that L-Glutamyl-L-Glycyl-L-Arginyl chloromethyl ketone (GGACK) and a specific polyclonal anti-u-PA-antibody (anti-u-PA-IgG) effectively inhibited urokinase-induced plasmin generation without interfering with haemostatic assays. The anti-u-PA-antibody afforded full protection of alpha 2-antiplasmin at therapeutic levels of u-PA. It is concluded that u-PA in plasma samples from patients during thrombolytic therapy may induce in vitro effects which should be prevented by the use of a suitable inhibitor such as GGACK or specific anti-u-PA-antibody.
Amino Acid Chloromethyl Ketones↗
Plasminogen activation at low temperatures in plasma samples containing therapeutic concentrations of tissue-type plasminogen activator or other thrombolytic agents.
It is known that in vitro plasminogen activation in blood samples taken during thrombolytic therapy with tissue-type plasminogen activator (t-PA) may lead to artefactually low fibrinogen and alpha 2-antiplasmin values. To mimic this phenomenon, pooled normal plasma was supplemented with 2.5 micrograms/ml t-PA and incubated at various temperatures. The rates of fibrinogen degradation and alpha 2-antiplasmin consumption were most pronounced at 37 degrees C, were less pronounced at 25 degrees C, but surprisingly, did not further decrease at 10 degrees C, 0 degrees C or -8 degrees C. In contrast, when plasma was supplemented with 160 IU/ml urokinase or 30 IU/ml streptokinase, the rates of fibrinogen degradation and alpha 2-antiplasmin consumption gradually decreased with incubation temperature and were negligible at 10 degrees C and lower temperatures. The rate of plasminogen activation also decreased gradually with temperature in mixtures of purified fibrinogen, plasminogen, alpha 2-antiplasmin and t-PA. These results imply that, in a plasma milieu, additional factors with a stimulatory activity are involved in t-PA-induced plasminogen activation at around 0 degrees C. The abnormally high reaction rate at low temperatures explains in vitro plasminogen activation observed during the processing of t-PA-containing blood samples. In contrast to the activation of plasminogen by t-PA, the slow inhibition of t-PA (2.5 micrograms/ml) by proteinase inhibitors in plasma could be minimized to a negligible level by keeping the plasma samples at 0 degrees C. This makes it possible to reliably monitor t-PA activity during thrombolytic therapy.
Chromogenic Compounds↗
[Prevention of thrombosis with low molecular weight heparin and hydroxyethyl starch in general surgery].
In an open, randomized, controlled and prospective study we compared the efficacy of LMWH with unfractionated heparin (UFH) and the effects of both heparin preparations on haemostatic and fibrinolytic parameters. We also stratified subgroups which received HES intra- and postoperatively. The study groups were well matched with regard to baseline characteristics. With LMWH 4 patients (4.1%) displayed a positive fibrinogen uptake test (1 patient with HES). With UFH 5 patients (5%) demonstrated a positive uptake (3 patients with HES). Antifactor Xa levels were significant higher in the LMWH groups; all other fibrinolytic and haemostatic factors, bleeding and local wound complications did not differ. These data suggest that LMWH in equally effective and safe as UFH in general surgery. HES may have and additive effect.
Adult↗