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G Stehle

Publications and source records attributed to G Stehle.

At least 37 records · Page 2Linked to original sources
PubMed1995

Comparison of immunological and functional assays for measurement of soluble fibrin.

Various assays have been developed for quantitation of soluble fibrin or fibrin monomer in clinical plasma samples, since this parameter directly reflects in vivo thrombin action on fibrinogen. Using plasma samples from healthy blood donors, patients with cerebral ischemic insult, patients with septicemia, and patients with venous thrombosis, we compared two immunologic tests using monoclonal antibodies against fibrin-specific neo-epitopes, and two functional tests based on the cofactor activity of soluble fibrin complexes in tPA-induced plasminogen activation. Test A (Enzymun-Test FM) showed the best discriminating power among normal range and pathological samples. Test B (Fibrinostika soluble fibrin) clearly separated normal range from pathological samples, but failed to discriminate among samples from patients with low grade coagulation activation in septicemia, and massive activation in venous thrombosis. Functional test C (Fibrin monomer test Behring) displayed good discriminating power between normal and pathological range samples, and correlated with test A (r = 0.61), whereas assay D (Coa-Set Fibrin monomer) showed little discriminating power at values below 10 micrograms/ml and little correlation with other assays. Standardization of assays will require further characterization of analytes detected.

Antibodies, Monoclonal↗
PubMed1993

Protamine neutralization of the release of tissue factor pathway inhibitor activity by heparins.

The present study was designed to investigate the action of protamine on the release of tissue factor pathway inhibitor (TFPI) activity by unfractionated (UF) and low molecular weight (LMW) heparin in healthy individuals. 5000 IU UF-heparin or 5000 IU LMW-heparin were given intravenously followed by saline, 5000 U protamine chloride or 5000 U protamine sulfate intravenously after the 10 min blood sample. Then serial blood samples for the measurement of TFPI activity and anti-factor Xa-activity were taken, in order to detect a possible relation between the remaining anti-factor Xa activity after neutralization of LMW-heparin with protamine and TFPI activity and to establish whether or not a rebound phenomenon of plasmatic TFPI occurs. There was no difference in the release and in the kinetics of TFPI by UF- and LMW-heparin with subsequent administration of saline. After administration of protamine TFPI activity decreased immediately and irreversibly to pretreatment values. There were no differences between protamine chloride and protamine sulfate on the effect of TFPI induced by UF- or LMW-heparin. No rebound phenomenon of TFPI activity occurred. In contrast anti-factor Xa- activity, as measured by the chromogenic S2222-assay, issued the known differences between UF- and LMW-heparin. The half-life of the aXa-effect of LMW-heparin was twice as long as of UF-heparin. Protamine antagonized UF-heparin completely and about 60% of the anti-factor Xa activity of LMW-heparin, using chromogenic S2222-method. No differences could be detected for protamine chloride and sulfate form of protamine. It is assumed that protamine displaces heparins from the binding sites of TFPI.(ABSTRACT TRUNCATED AT 250 WORDS)

Factor Xa Inhibitors↗
PubMed1993

Altered pharmacokinetic properties of a lipophilically derivatized low-molecular-weight heparin in rats.

A new generation of lipophilic heparins has been developed that show longer-lasting inhibitory effects on the coagulation system. We have studied the radiopharmacokinetics of a derivatized low-molecular-weight heparin (LMWH) with a residualizing lipophilic tyramine-deoxysorbitol label in comparison with conventional LMWH after intravenous application into Wistar rats. Whole body scintigraphy and analysis of the blood and organ distribution of different tracer preparations revealed that the lipophilically derivatized LMWH substance was predominantly trapped in the liver RES by a scavenger receptor-mediated mechanism. After the saturable uptake mechanism was blocked by maleylated bovine serum albumin, 41.4% of the lipophilic LMWH tracer circulated in blood, as compared with 18.4% of the control and 1% of conventional LMWH. The same results were attained by a competition experiment with an excess of unfractionated heparin. Urinary excretion of the lipophilic tracer among the rats in this competition experiment was considerably lower (13.7%) as compared with conventional LMWH (53.0%). Experiments with lipophilic LMWH tracer bound nonspecifically to rat serum albumin confirmed that the prolonged half-life might in part be due to an increased affinity for albumin. About 59% of the activity of the lipophilic tracer bound to albumin was found in the liver reticuloendothelial system, and only 3.3% were excreted to urine 3 hours after injection. Further studies are necessary to evaluate the accumulation rates and the metabolic fate of lipophilically derivatized heparins in the case of an impeded reticuloendothelial system uptake before attempts are made to therapeutically apply these compounds.

Albumins↗
PubMed1993

Prophylaxis of embolic events in patients with atrial fibrillation using low molecular weight heparin.

In patients with chronic nonrheumatic atrial fibrillation, prophylaxis of peripheral arterial embolism is strongly indicated. LMWHs may be an alternative regimen if contraindications for oral anticoagulants are present. In the present study the effect of LMWH on the incidence of embolism in atrial fibrillation has been studied in 75 consecutive patients in comparison to no specific treatment. Patients received one daily injection of the LMWH CY 216 (n = 35) subcutaneously over a period of 6 months. Patients of the control group (n = 40) were observed over the same period of time. In the group treated with CY 216, three embolic events (8.6%) occurred, of which two were localized in the cerebrum. One of these two cerebral embolic events was fatal. In the control group, eight embolic events (20%) occurred, six of these were intracerebral and, of these, five were fatal. An even more pronounced difference between the groups was observed on evaluation of the patients with preceding cerebral embolism. Of 15 patients treated with LMWH, one extracerebral nonfatal embolism occurred. In the control group three of the seven patients (43%) experienced fatal reembolism. The results show that in patients with atrial fibrillation one daily subcutaneous injection of LMWH reduces the incidence of arterial embolism to about one third. No adverse effects were observed during the 6-month treatment period with LMWH.

Aged↗
PubMed1992

Heparin Study in Internal Medicine (HESIM): design and preliminary results.

The Heparin Study in Internal Medicine (HESIM) compares the efficacy and safety of an unfractionated (UF) heparin with a low molecular weight (LMW) heparin (CY 216 D) for prevention of proximal deep vein thrombosis (DVT) and pulmonary embolism (PE) in medical inpatients with a high risk for development of thromboembolism. Patients are randomized and receive three times daily 5000 IU UF heparin or once daily 3100 IU LMW heparin and two placebo injections subcutaneously for 10 days. All patients are screened for the presence of proximal DVT at day 1 and 10 by real-time B-mode compression sonography and for PE by repeated clinical examinations. Perfusion scintigraphy is used for confirmation of the clinical diagnosis of PE. The study protocol includes a stratified randomization of patients on admission to the hospital according to one of the following main diagnoses: malignant disease, cardiovascular disease, bronchopulmonary disease, neurologic disease, and other diseases. The present study may serve as a model for further clinical trials in medical inpatients using the biometric approach of statistical analysis for proving equivalence of drug efficacy, and to adopt less sensitive but noninvasive methods for the detection of primary endpoints.

Aged↗
PubMed1992

Hepatic uptake of a modified low molecular weight heparin in rats.

Fractionated and unfractionated heparins are widely used as antithrombotic agents. Because of their heterogeneous composition, it is difficult to study the pharmacokinetics of these drugs. We now report on a new method for labeling low molecular weight heparins with 131I by binding tyramine to the anhydromannose end of the molecules. We examined the pharmacokinetics of the compound by intravenous injection of 131I-tyramine-heparin into Wistar rats. About 18% of the activity was found in the liver, whereas 33% was detected in urine. Biological activity in terms of Factor Xa inhibition was measurable. Since evidence from cell culture experiments implies that reticuloendothelial cell system receptors might be involved in heparin metabolism, maleylated BSA, a substance known to block scavenger receptors, was injected before the radiolabeled heparin compound. The liver uptake was reduced from 17.4 to 4.8%. Injection of unfractionated heparin before tracer application caused a considerable increase in urine excretion of the tracer substance. To our knowledge, this is the first report that liver uptake of heparins is linked to scavenger receptor mediated mechanisms in vivo. This interaction of heparins with scavenger receptors might play an important role in the biology of the vessel wall.

Animals↗
PubMed1992

Risk factor patterns for coronary heart disease in China, Japan and Germany.

The risk factor patterns for coronary heart disease in China, Japan and Germany were studied. 6,025 Germans, 7,580 Japanese and 2,047 Chinese aged 30-59 were investigated following the protocol of the Göttingen Risk, Incidence, and Prevalence Study carried out in West Germany in 1982. It is concluded that in China, the risk factor intervention focuses mainly on smoking and hypertension; smoking also remains the most important risk factor in Japan; while in Germany the major targets are obesity and hyperlipidemia. However, about 38% of the participants from West Germany showed 3 or more risk factors accumulated per person. Thus the multifactorial risk factor reduction might be necessary in Germany.

Adult↗
PubMed1991

Differences in the risk factor patterns for coronary heart disease in China, Japan, and Germany.

In Asia coronary heart disease mortality is almost 10 fold less frequent than in European countries. These findings attract interest to search for different risk factor patterns. From 1982 to 1985 epidemiologic surveys were carried out in China (n = 2047), Japan (n = 7580) and Germany (n = 6052). Healthy, male subjects, aged 30 to 59 years were enrolled. The prevalence rate of hypertension for the Germans was 20% versus 18% for the Japanese, and 11% for the Chinese. About 69% of Chinese, 55% of Japanese, and 37% of Germans were smokers. About 66% of the Germans were overweight (BMI greater than 25), 17% of the Japanese, and 11% of the Chinese. The highest risk group with cholesterol levels of greater than 300 mg/dl included no Chinese subject, 0.1% of the Japanese, but 5% of the Germans. The lipoprotein profiles among the Japanese and the Chinese collectives typically showed antiatherosclerotic characteristics, whereas most Germans exhibited profiles which support development of atherosclerosis. About 36% of the participants from Germany showed 3 or more risk factors accumulated per person (Japan and China 5%). Multifactorial risk factor reduction for Germany is recommended.

Adult↗
PubMed1991

Incidence and mortality rates of myocardial infarction in Chinese workers aged 40-59 in relation to coronary risk factors. Results of a Chinese prospective study (Wuhan Study) in comparison to the Göttingen Risk Incidence and Prevalence Study (GRIPS).

Some 2045 male Chinese industrial workers aged 40-59 years living in the city of Wuhan in the People's Republic of China were examined for coronary risk factors in the year 1983. The investigation included a patient history, clinical examination, and ECG and laboratory tests, with special attention to serum lipids. After 5 years, a follow-up investigation of the study group was carried out. The results were compared to the similarly designed German GRIPS project. In comparison to the German population, significantly lower levels for total-, LDL-, and VLDL-cholesterol, apolipoprotein B, triglycerides, uric acid, body mass index, and diastolic blood pressure were found in China. The percentage of smokers, however, was remarkably higher in China than in the Federal Republic of Germany. During the 5 year observation period in the Chinese sample, four subjects suffered from sudden death and four from nonfatal myocardial infarction; in the German study group three times as many fatal myocardial infarction and cases of sudden death and 7.5 times as many nonfatal myocardial infarctions were recorded. Nonfatal coronary heart disease and peripheral vascular disease were also observed less often in China. The incidence of cerebrovascular diseases was 1.5 times higher in China than in Germany. Whereas in Germany, total-, and LDL-cholesterol values were the major distinguishing parameters between infarction and reference groups, in China these values have thus far had no significant influence on the level of risk. Instead in the Chinese incidence group, significantly higher levels for blood pressure, body mass index, uric acid, and the ratio LDL/HDL-cholesterol were found.

Adult↗
PubMed1990

Therapeutic application of subcutaneous low-molecular-weight heparin in acute venous thrombosis.

Fifty patients presenting with acute deep-vein thrombosis were randomized in a prospective, controlled study to determine the safety and efficacy of a treatment with low-molecular-weight (LMW) heparin compared with unfractionated heparin. LMW heparin (n = 24) was administered twice daily subcutaneously at a dose of 2 X 150 anti-Xa units/kg body weight, and unfractionated heparin (n = 26) was given intravenously by continuous infusion at a dose of 450 anti-Xa units/kg body weight daily for 10 days. Doses were adjusted to maintain peak anti-Xa levels between 0.5 and 1.0 anti-Xa units per milliliter. One patient in the unfractionated heparin group and 2 patients in the LMW heparin group suffered from bleeding complications. Two patients on LMW heparin and on unfractionated heparin had high evidence of pulmonary embolism based on defects on ventilation-perfusion scintigraphy. Control phlebography and duplex sonography demonstrated a significant improvement during both treatment regimens. Reperfusion of the deep-vein system was 70% with LMW heparin and 75% with unfractionated heparin. The anti-Xa levels were significantly higher in the LMW heparin group, and activated partial thromboplastin and thrombin clotting times were significantly higher in the group receiving unfractionated heparin. Thrombin-antithrombin III complexes and D-dimer concentration decreased during the treatment, but did not differ between the two regimens. At the end of the treatment period with LMW heparin, protein C and antithrombin III were significantly higher.

Acute Disease↗
PubMed1989

Biological activity and safety of the subcutaneous administration of high doses of low molecular weight heparin for 8 days in human volunteers.

This study reports on the biological activity and safety of high dose low molecular weight (LMW) heparin therapy administered by two subcutaneous (s.c.) injections daily for 8 days in healthy human volunteers. Group 1 received 2 x 30 aPTT units LMW heparin/kg bodyweight, and group 2 received 2 x 50 aPTT units/kg per day. In group 1, activated partial thromboplastin time (aPTT) and thrombin clotting time (TCT) were uniformly prolonged by 3-5 sec 4 hrs after s.c. administration of heparin. Heptest coagulation time values were prolonged consistently as well by 57 sec on day 1 to 68 sec on day 8. Factor Xa inhibition measured by the S 2222 chromogenic substrate method continuously increased from 0.16 units/ml on day 1 to 0.28 units/ml on day 8. In group 2 prolongation of a aPTT and TCT values increased from 6 sec on day 1 to 15 sec on day 8 and of Heptest time from 70 sec on day 1 to 110 sec on day 8. S 2222 method showed factor Xa inhibitory activity which increased from 0.5 units/ml on day 1 to 0.75 units/ml on day 8. The clinical tolerance of the treatment was good. No changes in clinical chemistry parameters were detected, except for a reversible increase of serum transaminases. The coagulation studies demonstrate accumulation of LMW heparin when high doses are given twice daily. The half life of LMW heparin of factor Xa inhibition increases with increasing doses. Heptest coagulation values were prolonged to 4-6 times the normal values during administration of heparin.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Comparative human pharmacology of low molecular weight heparins.

The pharmacodynamics of LMW heparins differ consistently from those of normal heparin. The relative bioavailability is greater than 90% and for some LMW heparins more than 100% after subcutaneous administration, as measured by the anti-Factor Xa activity. This indicates release of endothelial bound glycosaminoglycans with anti-Factor Xa-like activities. Direct determination of the LPL and HTGL activities demonstrate higher capacities of two and a lower capacity of three LMW heparins to release these enzymes from their endothelial glycoprotein receptors into the bloodstream. Thus, all LMW heparins are characterized by improved pharmacodynamics compared with normal heparin, but their anti-Xa to APTT and anti-Xa to anti-IIa ratios and half-lives differ among each other. The neutralization of the anticoagulant effects of LMW heparins by protamine are similar in vitro and in vivo at equigravimetric doses. However, unfractionated heparin and LMW heparins are not completely antagonized by protamine on a whole blood clotting test (thrombelastography). This inhibition of Factor Xa of LMW heparins is counteracted not completely by protamine. This may be due to a release of other glucosaminoglycans by LMW heparins. The present overview demonstrates that a comparative human pharmacology gives useful devices for prophylactic and therapeutic regimen for LMW heparins in patients in addition to the data obtained from animal models.

Animals↗
PubMed1989

The pharmacological profile of the low molecular weight heparin 21-23 in man: anticoagulant, lipolytic and protamine reversible effects.

The anticoagulant, lipolytic and protamine reversible effects of high doses of low molecular weight (LMW) heparin 21-23 and unfractionated heparin were compared in man. 7,500 units of each heparin were applied, which corresponds to 90 mg LMW heparin and 48 mg unfractionated heparin. The anticoagulant properties of the LMW heparin are characterized by a doubled half life of factor Xa activity, smaller influence on aPTT and thrombin after intravenous (i.v.) and subcutaneous (s.c.) injection, and higher bioavailability of factor Xa activity after s.c. administration (90% versus 15%). Protamine chloride completely neutralizes the effect on aPTT and thrombin and reduces the anti factor Xa activity by 60%. The bleeding time is prolonged by both normal and LMW heparin by 20%. This effect is normalized by protamine chloride, too. Thrombelastography with recalcified whole blood demonstrates that protamine chloride shortens but not completely normalizes the coagulation time in presence of either unfractionated or LMW heparin. The half life of lipoprotein lipase (LPL) activity is 60 min after i.v. administration of unfractionated heparin and 120 min with LMW heparin. Although the release of lipases (LPL and HTGL) is higher after i.v. and s.c. administration of the LMW heparin they do not induce higher releases of free fatty acids. This indicates that the lipolytic activity of this LMW heparin and unfractionated heparin is similar. The results show an improved anticoagulant pharmacological profile of this LMW heparin as compared to unfractionated heparin. Protamine normalizes the anticoagulant effects of LMW heparin with exception of a residual anti factor Xa activity and normalizes the changes of bleeding time and thrombelastography.

Adult↗
PubMed1988

Monitoring of heparin and low molecular weight heparin with capillary and venous whole blood.

A method for determination of antifactor Xa-like activity in capillary whole blood obtained from the fingertip is described, which employs the Heptest coagulation assay. Values obtained with capillary whole blood are compared to values of corresponding plasma and venous whole blood samples. Normal values in plasma, venous whole blood, and capillary blood from the fingertip were 17.1 +/- 2.1, 10.0 +/- 1.3 and 10.4 +/- 1.3 sec, respectively. The intraindividual coefficients of variations range from 0.4 to 1.8% in all assays. The day to day coefficient of variation of normal values ranged between 0.8 and 2.0% for all assays. The within assay coefficients of variation ranged from 3.0 to 7.7% for whole blood samples and from 1.5 to 2.2% for plasma samples after addition of no, 0.2 or 1.0 units of normal or LMW heparin to the samples. After administration of heparin or LMW heparin in healthy persons the coagulation values of the different coagulation assay systems displayed coefficients of correlation between r = 0.87 and r = 0.95. Correlation coefficients between the coagulation tests and the S 2222 chromogenic substrate method ranged from r = 0.77 to r = 0.92. In patients, who received LMW heparin for prophylaxis of thromboembolism the coagulation assay correlated between r = 0.78 and 0.92. The coagulation assays and the S 2222 method displayed coefficients of correlation between r = 0.74 and r = 0.83. The data indicate that Heptest sensitively measures antifactor Xa-like activity in capillary whole blood as well as venous whole blood samples containing low quantities of heparin or LMW heparin.

Adult↗
PubMed1986

Review and current status of thrombolytic therapy with streptokinase.

In 1933 Streptokinase (SK) was isolated from bacterial strains of haemolytic Streptococci. Since then it has become the widest spread drug for fibrinolysis. SK, a protein, consists of 415 aminoacids and has a molecular weight of 47,000u. Together with the plasminogen (PLG) of the blood it forms activator complexes, which then convert other PLG molecules of the blood to plasmin. Plasmin attacks and dissolves fibrin deposits. As a substance produced by bacteria SK stimulates antibody formation in the body, the titer will increase during therapy, and SK lysis should be terminated after 6 days of treatment. Usually SK is administered intravascularly to treat a wide range of diseases, associated with pathological activation of hemostasis, like deep vein thrombosis, pulmonary embolism, myocardial infarction etc.. Contraindications can be traced back to the effects of SK on coagulation and the immune system. Bleeding is the most common side effect, but also a few anaphylactic reactions, caused by massive antigen-antibody precipitation have been observed. The rate of lethality of the treatment was established at 0.7% of the cases. To reduce the incidence of side effects modifications of the drug have been proposed, such as activator complex, light B chain SK, and acylated activator therapy. Compared with Urokinase, SK shows a higher rate of side effects, especially in the field of the immune system. Therapy with Urokinase can be controlled more easily. Nevertheless because of considerable price differences and logistics, SK is preferred in Europe and the USA. If strict guidelines in therapeutic use are followed, the rate of side effects of the drug can be curtailed and will be comparable to those of Urokinase.

Humans↗