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Biomedical subjects

C E Dempfle

Publications and source records attributed to C E Dempfle.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1993

Binding of a new monoclonal antibody against N-terminal heptapeptide of fibrin alpha-chain to fibrin polymerization site 'A': effects of fibrinogen and fibrinogen derivatives, and pretreatment of samples with NaSCN.

A novel murine monoclonal antibody against the fibrin alpha-chain N-terminus is presented, which reacts with desAA- and desAABB-fibrin. In immunoblot procedures, the antibody reacted with fibrin degradation products X and Y of non-crosslinked fibrin, and fragment E. No binding was observed to the fibrin fragment D-dimer, and fibrinogen fragments D and E. Minor binding to fibrinogen fragments X, and Y, and desBB-fibrin were presumably due to minor contamination with (desAA)-fibrin. A prerequisite for binding was release of fibrinopeptides A (FpA), the binding site being a fibrin-specific neo-epitope. No binding was observed to fibrinogen or to thrombin-treated dysfibrinogen MANNHEIM III (A alpha 16 Arg-->Cys) molecules, which do not release FpA. The antibody bound to abnormal fibrin molecules prepared from dysfibrinogen MANNHEIM I (A alpha 19 Arg-->Gly), albeit to a lesser extent than to normal fibrin. Binding of the antibody to the fibrin epitope was greatly enhanced by denaturation, e.g. by heat, or by treatment with chaotropic ions. Soluble fibrin in clinical samples is generally found as a complex with fibrinogen, since polymerization sites 'A' exposed by release of FpA react with complementary binding sites 'a' on the D-domains of other fibrin and fibrinogen molecules. Treatment of samples with NaSCN caused dissociation of fibrin monomer complexes. Reassociation was prevented by denaturation of both polymerization sites 'A' and 'a'. The antibody in combination with NaSCN-treatment of samples was useful for specific detection of fibrin monomer in plasma samples. Measurement was not influenced by fibrinogen degradation products, whereas fibrin degradation products at very high concentration caused some underestimation of fibrin monomer concentration.

Animals↗
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

Microtiter assay for measurement of factor XIII activity in plasma.

A sensitive, reproducible and rapid quantitative microtiter assay for factor XIII activity is described. The assay is based on incorporation of a soluble amine substrate into casein attached to polystyrol microtiter plates and detection of bound substrate with a monoclonal antibody-enzyme conjugate. Defibrination of plasma samples is not required. The assay shows strong correlation with the immunologic assay for factor XIII catalytic subunit a (r = 0.94), the factor XIII dansylcadaverine assay (r = 0.83), and the factor XIII clot solubility test. Normal values detected in healthy blood donors were in the range of 74% to 117%, with a mean value of 96.9% and a median value of 97.8%; pooled normal plasma was used as a reference. Since the assay is performed in a single microtiter plate and requires few reagents and short incubation periods, it can be easily adapted for clinical use.

Caseins↗
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↗
PubMed1992

[Endometriosis of the terminal ileum--differential diagnosis of Crohn disease].

Ileocecal resection was performed in two female patients with stenosis of the terminal ileum. Histological findings confirmed the clinical diagnosis of Crohn's disease in the first case, although focal intestinal endometriosis was detected. The resection specimens of the other patient exclusively showed lesions of endometriosis extending from the subserosa to the mucosal tissue. Typical lesions of Crohn's disease were totally absent in this case. Although not very frequent, endometriosis is an important differential diagnosis of Crohn's disease in young females.

Adult↗
PubMed1990

Randomized controlled study of heparin and low molecular weight heparin for prevention of deep-vein thrombosis in medical patients.

166 patients aged 40-80 years were included in a controlled, randomized, double-blind study to determine the efficacy and safety of a single daily injection of a low molecular weight (LMW) heparin for prevention of deep-vein thrombosis compared to low dose conventional heparin. Patients received 1 x 1.500 aPTT units of a LMW heparin fraction (plus 2 x placebo injection) or 3 x 5.000 IU of an unfractionated heparin. During 10 days of treatment, patients underwent repeated clinical investigation, serial impedance plethysmography, and Doppler sonography for detection of thrombosis of the lower limbs. Combined application of these methods revealed evidence of thrombosis in 4.5% of patients on unfractionated heparin and 3.6% of patients on LMW heparin. Subcutaneous hematomas were significantly smaller in diameter upon treatment with LMW heparin (p less than 0.001). Antithrombin III levels were significantly higher at the end of the observation period in the LMW heparin group (p less than 0.005). Thrombocyte count, transaminases, creatinine, and haemoglobin did not change in either group. The results indicate that LMW heparin administered by a single s.c. dose daily may be as effective as low dose heparin in prevention of deep venous thrombosis in medical inpatients.

Adult↗
PubMed1990

Coagulopathy after snake bite by Bothrops neuwiedi: case report and results of in vitro experiments.

Coagulation studies were performed in a patient who had been bitten by a snake of the species Bothrops neuwiedi. The patient presented with hemorrhagic necrosis at the envenomization site and considerable bleeding from venous puncture sites. He developed a severe defibrination syndrome with a clottable fibrinogen level of approximately 0.1 g/l. Fibrinogen was not measurable by clotting time assay. Fibrin degradation products were greatly elevated. Treatment with antivenom caused an anaphylactic reaction within ten minutes and serum sickness after three days. In vitro experiments revealed that B. neuwiedi venom directly activates Factors II and X, but does not activate Factor XIII. In vivo consumption of Factor XIII after B. neuwiedi envenomization is ascribed to the action of Factor IIa. At low venom concentrations clotting is initiated by activation of prothrombin by the venom either directly or via Factor X activation. Treatment with heparin might be beneficial in coagulopathy secondary to snake bite by reducing circulating active thrombin. The venom contains thrombin-like proteases which cause slow clotting of fibrinogen, and plasmin-like components causing further proteolysis of fibrinogen and fibrin. Antivenom has no effect on the proteolytic action of the snake venom. The in vivo effects of antivenom are presumably caused by acceleration of the elimination of venom components from the circulation. Intravenous administration of antivenom caused normalization of blood coagulation parameters within 48 h.

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

Impaired fibrinolytic capacity and tissue plasminogen activator release in patients with restenosis after percutaneous transluminal coronary angioplasty (PTCA).

To assess the role of the fibrinolytic system in the pathogenesis of restenosis after percutaneous transluminal coronary angioplasty (PTCA), we determined the components of this system in a retrospective study, including 16 patients with restenosis (gr. A) and 19 patients with long-term success (gr. B). In both groups at baseline fibrinolytic activity (FA) is unchanged, whereas tissue plasminogen activator antigen (tPA-Ag) is significantly increased (gr. A: 147.0%; gr. B: 139.8%; p less than 0.01). Fibrinolytic capacity (FC) and tPA-Ag release are significantly reduced in the restenosis group (FC: 46.5%, p less than 0.05; tPA-Ag release: 48.3%, p less than 0.01) compared to normal controls as well as to gr. B (FC: 84.3%, p less than 0.05; tPA-Ag release: 79.0%, p less than 0.05). Relating to the contact activation system, F XII (79.5%, p less than 0.05) is significantly, and F XI (82.3%) is clearly reduced in gr. A. Protein C (PC) is significantly elevated in gr. B (117.5%, p less than 0.05). There is a negative correlation between plasminogen activator inhibitor (PAI 1) and HDL-cholesterol (r = 0.37, p less than 0.05). It appears, that there is a typical pattern of defective fibrinolysis in patients with restenosis after PTCA and that this might be a pathogenetic factor in the development of restenosis.

Angioplasty, Balloon, Coronary↗
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

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↗
PubMed1989

Long term anticoagulation with low molecular weight heparin in outpatients with side effects on oral anticoagulants.

A total of 70 outpatients with previous severe haemorrhages and other side effects on conventional oral anticoagulants given for prophylaxis of tromboembolism, were treated with low molecular weight (LMW) heparin fraction Kabi 2165. Anticoagulation was necessary in all patients because of recurrent venous thromboembolism (n = 39), artificial heart valve replacement (n = 12), atrial fibrillation with peripheral embolism (n = 10), and cardiomyopathy (n = 9). LMW heparin was injected sc at doses ranging from 2,500 to 15,000 antifactor Xa (aXa) units once daily by the patients themselves. The dose was adjusted on the basis of body weight, of bleeding risk, and risk of developing thromboembolism. Five of 70 patients with poor compliance, 3 experienced non fatal embolism during the treatment period. Two of 65 patients with good compliance experienced repeat embolism. No fatal embolism occurred. One major episode of gastrointestinal bleeding occurred in a patient with an undetected colon carcinoma. Nine minor hemorrhages were observed in all patients. The present experience suggests that LMW heparin may be used safely and effectively as an alternative anticoagulant in patients who have experienced bleeding and other complications with oral anticoagulants or conventional heparin.

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↗
PubMed1987

Isolation and purification of fibrinogen/fibrin degradation products by chromatography on protamine-agarose.

Protamine-agarose chromatography is introduced as a rapid and efficient method for the isolation of fibrinogen/fibrin degradation products from biological fluids such as human plasma. All fibrinogen/fibrin fragments above a MW of 35000, including fragments D and E are quantitatively adsorbed to insolubilized protamine and can be eluted with a buffer containing 0.2 M sodium citrate/citric acid pH 5.3, following previous elution of non-fibrinogen proteins with a buffer containing 0.8 M NaCl at neutral pH. Fragments D and E are separated by stepwise elution. The efficiency of the method is - evaluated by applying it to plasma samples obtained from healthy donors and from patients with clinical and laboratory evidence of disseminated intravascular coagulation.

Chromatography, Agarose↗
PubMed1987

Purification of human plasma fibrinogen by chromatography on protamine-agarose.

A study was performed to investigate if protamine covalently attached to CNBr-activated agarose is a useful tool for the purification of fibrinogen from human plasma samples. One chromatography step yielded a preparation with a clottability greater than 90% from platelet-poor plasma with a yield of 65-80% of fibrinogen applied. The preparation is free of plasminogen, immunoglobulins, fibronectin, albumin, antithrombin III, alpha 2-macroglobulin, and alpha 1-antitrypsin, as determined by immunological and functional methods. 6.5 mg of fibrinogen were adsorbed to 1.0 ml of protamine-agarose. Protamine-agarose chromatography can be applied to plasma samples as small as 200 microliters.

Adsorption↗