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Biomedical subjects

C E Dempfle

Publications and source records attributed to C E Dempfle.

At least 37 records · Page 2Linked to original sources
PubMed1999

Fibrin monomer antigen: a novel marker of mortality in acute myocardial infarction.

AIMS: A novel sensitive method for analyses of soluble fibrin monomer antigen was used to assess the predictive value of fibrin monomer when estimating mortality after acute myocardial infarction. METHODS AND RESULTS: Fibrin monomer was measured in plasma samples from 293 patients enrolled in a randomized clinical trial of low molecular weight heparin (dalteparin) in acute myocardial infarction (the FRAMI trial). Samples taken on days 2 and 7 were analysed using the Enzymun-Test FM(R)(Boehringer Mannheim, Germany). Non-survivors had significantly higher fibrin monomer levels relative to survivors (day 2, median (min-max): 1.8 mg. l-1(<0.01-73.1) vs 0.4 mg. l-1(<0. 01-103.5), P<0.0001). Fibrin monomer levels were significantly associated with congestive heart failure (P<0.001), enzymatic infarct size (P<0.0001), dalteparin treatment (P<0.001), and thrombolytic therapy (P=0.016). The relationship between fibrin monomer and mortality remained statistically significant after adjustment for these variables. In logistic regression analyses, fibrin monomer levels, age and congestive heart failure were all independent predictors of fatal outcome. CONCLUSIONS: Increased fibrin monomer level is an independent predictor of mortality in patients with myocardial infarction. It allows further risk stratification when combined with known risk factors such as age and presence of congestive heart failure.

Aged↗
PubMed1999

A 96-well microfiltration assay for measurement of total clottable fibrinogen.

In clinical routine use, fibrinogen is measured by clotting-time methods, or by clot turbidity in photometric prothrombin time determination. For calibration of these assays measurement of total thrombin-clottable protein has been recommended. We have now developed a microfiltration assay for total thrombin-clottable protein. Plasma samples were mixed with thrombin in a 96-well microfiltration device. After clot formation, the fluid was extracted by vacuum suction, and fibrin adherent to the filter membranes washed with buffer. Membrane segments with adherent fibrin were recovered from the 96-well manifold with a punch and transferred to tubes containing denaturing buffer solution. After dissolution of fibrin, protein concentration was determined by optical absorption at 280 nm. The microfiltration assay displayed a high correlation with the total clottable protein method (R = 0.95), and fibrinogen antigen (r = 0.96). Correlation with clotting time assays, and PT-derived fibrinogen in 150 clinical plasma samples was in the range of r = 0.84 to r = 0.97. Intraassay and day-to-day variability of the assay was comparable to the conventional total clottable fibrinogen assay. The novel microfiltration assay appears to be well suited for measurement of large series of samples for calibration, screening purposes, and clinical trials.

Blood Coagulation↗
PubMed1999

Predictive value of coagulation markers concerning clinical outcome 90 days after anterior myocardial infarction.

To study the predictive value of coagulation markers concerning clinical outcome, prothrombin fragment F1.2 (F1.2), fibrin monomer antigen (FM), D-Dimer (DD), and fibrinogen were measured in plasma samples drawn 2 and 7 days after acute myocardial infarction (AMI) in 314 consecutive patients randomized in a clinical trial of low molecular weight heparin (Dalteparin) (the FRAMI trial). Placebo-treated patients suffering death or new AMI within 90 days had significantly higher levels at day 2 of FM (Enzymun-Test FM), and DD (TINAquant D-dimer) (p = 0.001 and 0.02, respectively), but not F1.2 (Enzygnost F1.2 micro), relative to those without serious clinical events. At day 7 all three coagulation activation markers were significantly higher in patients with subsequent adverse clinical outcome. The Dalteparin group had significantly lower levels of these markers as compared to the placebo group. Left ventricular (LV) thrombus formation was not associated with changes in coagulation activation. However, patients with thrombus had significantly higher fibrinogen levels than those without thrombus (p = 0.004 day 2), independent of treatment group. Thus, markers of coagulation activation may be useful in stratification of patients when estimating risk for adverse clinical outcome after AMI. Furthermore, elevated fibrinogen levels are associated with increased risk of LV thrombus formation.

Anticoagulants↗
PubMed1999

Changes in coagulation and fibrinolysis markers in acute ischemic stroke treated with recombinant tissue plasminogen activator.

BACKGROUND AND PURPOSE: Shifts of the balance between coagulation and fibrinolysis play a crucial role in pathogenesis and treatment of cerebral ischemia. In this study, we characterized the kinetics of hemostatic abnormalities induced by acute ischemic stroke and its thrombolytic (recombinant tissue plasminogen activator [rtPA]) or anticoagulant (heparin) treatment. METHODS: Systemic generation of molecular markers of hemostasis (fibrin monomer, D-dimer, thrombin-antithrombin complex, and fibrinopeptide 1.2) was monitored in acute ischemic stroke, and the effects of thrombolytic and anticoagulant treatments were analyzed. RESULTS: Thrombolysis with rtPA induced a massive response of markers of coagulation activation and fibrin formation that peaked after 1 to 3 hours and persisted for up to 72 hours. In contrast, only minor hemostatic changes were induced by acute ischemic stroke itself. Administration of heparin did not significantly affect these hemostatic abnormalities. CONCLUSIONS: This first characterization of the coagulation activation induced by rtPA treatment for acute ischemic stroke and the failure to abolish such hemostatic abnormalities by heparin may be of value for further refinement of the currently discussed thrombolytic therapy and the controversial adjunctive anticoagulant prophylaxis in stroke patients.

Aged↗
PubMed1999

The use of soluble fibrin in evaluating the acute and chronic hypercoagulable state.

Soluble fibrin detected in clinical plasma samples includes a variety of complexes consisting of fibrin monomer units, fibrinogen, and various proteolytic derivatives of fibrinogen and fibrin. The advantage of measuring soluble fibrin over fibrinopeptide A to detect thrombin action on fibrinogen is the considerably longer half-life of soluble fibrin in the circulation. Soluble fibrin can be detected by a variety of methods, including paracoagulation and precipitation assays, adsorption of fibrin monomer to insolubilized fibrinogen, functional assays based on the cofactor activity of some soluble fibrin compounds in t-PA-induced plasminogen activation, and by using fibrin-specific antibodies. Fibrin-specific antibodies may react with epitopes generated directly by fibrinopeptide A or B release or with epitopes generated by fibrin polymerization. Epitopes dependent on fibrinopeptide A release are often not accessible in native fibrin complexes and require the disaggregation of fibrin compounds to be reactive, whereas epitopes dependent on fibrinopeptide B release or fibrin polymerization are accessible to the monoclonal antibodies in nondenatured fibrin. Since soluble fibrin assays detect different structural or functional properties of soluble fibrin, no common calibrator for all soluble fibrin assays and, often, little correlation between different assay systems in clinical evaluations exist. Clinical applications of soluble fibrin assays include diagnosis and treatment monitoring of intravascular coagulation processes and prethrombotic states, monitoring anticoagulant treatment, and biocompatibility investigations. Some soluble fibrin assays have been demonstrated to be extremely sensitive indicators of acute fibrin formation. For the exclusion of venous thrombosis, D-dimer assays appear to be more sensitive than current soluble fibrin assays, since D-dimer assays detect freshly formed fibrin and proteolytic fragments of particulate clots. Further clinical studies are needed to establish the clinical utility of specific, soluble fibrin assays. The development of rapid, quantitative soluble fibrin assays for clinical routine use should be encouraged.

Acute Disease↗
PubMed1997

Proinflammatory cytokines: indicators of infection in high-risk patients.

Proinflammatory cytokines play an eminent role in pathophysiology of infection and inflammation. Their actual clinical importance is, however, uncertain. In this study, we tested the hypothesis that inflammatory cytokines could be useful in detection of infections in high-risk patients. We prospectively studied the diagnostic value of determination of concentrations of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and the 55- and 75-kd soluble TNF receptors (sTNFR-p55 and sTNFR-p75) in detection of nosocomial infections in 52 patients with acute ischemic stroke, as an exemplary high-risk group, and compared these findings to those of conventional inflammatory indicators of inflammation (C-reactive protein and leukocyte count). After 1 week of hospitalization, 27% of the patients had minor or moderately severe nosocomial infections. This subpopulation exhibited significantly increased concentrations of IL-6 and sTNFR-p55 but not of IL-1beta, TNF-alpha, or sTNFR-p75. As expected, levels of C-reactive protein and leukocytes were increased in infected patients. The sensitivity and specificity for detection of nosocomial infections at day 7 of hospitalization was highest for IL-6, followed by C-reactive protein and the leukocyte count. The data suggest that the proinflammatory cytokine IL-6, in addition to its considerable pathophysiologic importance in systemic inflammation, may be valuable in detection of infections in high-risk patients.

Adult↗
PubMed1997

Histological changes in the colonic mucosa following irrigation with short-chain fatty acids.

OBJECTIVES: Short-chain fatty acids (SCFAs) derived from bacterial fermentation of complex carbohydrates are preferred luminal nutrients of the colonic mucosa. Starvation of colonocytes through lack or impaired metabolism of luminal SCFAs may be a cofactor in the pathogenesis of ulcerative colitis. DESIGN: A detailed histological evaluation of colonic biopsy specimens was performed in patients with active distal ulcerative colitis who were treated with rectal enemas containing a mixture of SCFAs, n-butyrate alone or saline placebo. Together with light microscopic parameters of mucosal inflammation, the pattern of crypt cell proliferation (proliferating cell nuclear antigen) and the mucosal activity of factor XIII were assessed. RESULTS: Butyrate reduced the density of polymorphonuclear leucocytes in the lamina propria (4 weeks: P = 0.063; 8 weeks: P = 0.091); other inflammatory parameters remained unchanged. Both butyrate and the SCFA mixture reduced significantly the number of proliferating cells in the upper 40% of crypts. Tissue factor XIII activity in active ulcerative colitis was significantly lower than in mucosa from normal colons; however, it was not affected by SCFA or butyrate irrigation. CONCLUSION: SCFAs and butyrate have a more marked effect on crypt cell proliferation than on parameters of inflammation in patients with active ulcerative colitis.

Adult↗
PubMed1997

Fibrinogen heterogeneity in homozygous plasminogen deficiency type I: further evidence that plasmin is not involved in formation of LMW- and LMW'-fibrinogen.

Human plasma fibrinogen is heterogeneous in SDS-polyacrylamide gel electrophoresis and other methods for separation of proteins by molecular size. A high molecular weight fraction (HMW-fibrinogen, 340 kD) contributes approximately 50% of total fibrinogen antigen. Low molecular weight fibrinogen (LMW-fibrinogen, 300 kD) adds another 40%. The residual amount is LMW'-fibrinogen with a molecular weight of 280 kD, and a small amount of very high molecular weight fibrinogen (Fib420), the product of alternative splicing of the A alpha-chain genetic information, resulting in an extended A alpha-chain C-terminus. Fibrinogen was detected by specific immunostaining of nonreduced SDS-PAGE gel immunoblots with antibodies against fibrinopeptide A. Using densitometric scans of the immunoblots we found a ratio of HMW-, LMW- and LMW'-fibrinogen in a patient with homozygous plasminogen deficiency that was similar to the ratio found in immunoblots of plasma from healthy blood donors. Treatment with plasminogen concentrate resulted in a slight decrease of the proportion of HMW-fibrinogen, followed by an increase to 78%. The LMW'-fibrinogen band gained intensity initially, increasing to 11.9% of fibrinogen antigen 6 h after starting plasminogen infusion, but then dropped to levels below detection limit of the immunoblotting assay. LMW-fibrinogen remained constant during the initial 72 h of plasminogen treatment, then dropping to values in the range of 22-25% afterwards. The proportion of HMW-, LMW-, and LMW'-fibrinogen again reached the initial levels two weeks after starting treatment with plasminogen concentrate. We conclude that plasminogen is not involved in the limited proteolysis leading to formation of LMW-fibrinogen and LMW'-fibrinogen in the absence of a generalized fibrinolytic condition. Fibrinolytic activation may lead to the formation of fibrinogen degradation product X, which appears in a similar position as LMW'-fibrinogen in SDS-PAGE.

Alternative Splicing↗
PubMed1997

Fibrin detected in plasma of patients with disseminated intravascular coagulation by fibrin-specific antibodies consists primarily of high molecular weight factor XIIIa-crosslinked and plasmin-modified complexes partially containing fibrinopeptide A.

Pooled plasma from 40 patients with severe disseminated intravascular coagulation (DIC) secondary to septic conditions was subjected to gel permeation chromatography on Sephacryl S-500 HR after sample pretreatment with KSCN for dissociation of non-covalent fibrin complexes. Fibrin antigen in eluates was detected by an array of ELISA tests, using two monoclonal antibodies against fibrin degradation product D-dimer, a monoclonal antibody against an epitope generated by plasmin cleavage of the D-domain, and an antibody against the neo-N-terminus of the alpha-chain of fibrin exposed by cleavage of fibrinopeptide A. Tag antibodies were a polyclonal antibody against the fibrinogen/ fibrin D-domain, a POD-conjugated version of the monoclonal antibody against fibrin alpha-chain neo-N-terminus, and a polyclonal antibody against fibrinopeptide A. Most fibrin-related material present in the pooled DIC plasma was of higher molecular mass than fibrinogen. Fibrin polymers were reactive with antibodies against D-dimer, plasmin cleaved D-domain, and fibrin alpha-chain neo-N-terminus. Part of the polymers reacted with antibodies against fibrinopeptide A, indicating presence of fibrinogen or desA-fibrin monomer within the covalently linked complex. In conclusion, the primary analytes detected by monoclonal antibodies for D-dimer, plasmin-specific epitopes of fibrin degradation products, as well as sites exposed by fibrinopeptide cleavage in plasma from patients with disseminated intravascular coagulation are high molecular weight factor XIIIa-crosslinked fibrin complexes, containing plasmin-cleaved D-domains, intact fibrin monomer units, and fibrinogen or desA-fibrin monomer.

Antibodies, Monoclonal↗
PubMed1996

Isolation and characterization of the fibrin intermediate arising from cleavage of one fibrinopeptide A from fibrinogen.

The thrombin-catalyzed cleavage of N-terminal fibrinopeptide A (FPA) from the two Aalpha-chains of fibrinogen exposes aggregation sites with the critical sequence GPR located just behind FPA. It is well known that exposure of both GPR sites transforms fibrinogen into self-aggregating, fully coagulable alpha-fibrin monomers, but the fibrin precursor with one site exposed and one FPA intact has eluded description. The formation of this "alpha-profibrin" in the course of thrombin reactions and its distribution among both the aggregating and non-aggregating components of the reactions are characterized here by immunoprobing electrophoretic and gel chromatographic separations using monoclonal antibodies specific for FPA and for exposed GPR sites. These analyses show alpha-profibrin to be a non-aggregating derivative indistinguishable from fibrinogen in solutions that are rich in fibrinogen relative to dissolved fibrin. But alpha-profibrin forms soluble complexes with alpha-fibrin monomer under conditions in which it and fibrin predominate over fibrinogen. It was isolated as a complex with fibrin by gel chromatography of cryoprecipitates and then separated from the fibrin either by electrophoretic gel shifts induced with a peptide analog of the GPR aggregation site or by chromatographic gel shifts induced with monoclonal anti-FPA antibody. The weak aggregation of alpha-profibrin with itself and with fibrinogen conforms with prior indications that coupled interactions through the paired GPR sites on fibrin monomers are pivotal to their aggregation. It is suggested that alpha-profibrin may be a hypercoagulable fibrin precursor because it is converted to alpha-fibrin monomer faster than fibrinogen converts to monomer.

Amino Acid Sequence↗
PubMed1996

The value of quantitative fibrin monomer determination in the early diagnosis of postoperative deep vein thrombosis.

A new test for the determination of fibrin monomer in plasma was clinically evaluated in comparison to the plasma concentration of D-D, TAT and F1,2 for the early diagnosis of prethrombotic conditions. For this purpose 129 patients who underwent abdominal surgery were followed longitudinally. 12 patients developed DVT postoperatively, proved by phlebography. The identical specificity level 73.2% was chosen for all 4 tests. At this specificity, FM had the highest sensitivity (91.7%), followed by D-D (75.0%), TAT (41.7%) and F1,2 (33.3%). All FM-positive DVT-patients had pathological FM-values at least one day prior to the clinical manifestation of thrombosis. In a group of 255 obviously healthy persons the cut-off value for the new FM test was determined at 3.6 mg/l (95th percentile). No clinically relevant influence of gender, age, smoking habits or oral anticonception could be observed. It is concluded that FM is a valuable diagnostic tool for the early diagnosis of prethrombotic conditions.

Abdomen↗
PubMed1995

The injection of heparin prolongs the plasma clearance of oxidized low density lipoprotein in the rat.

There is evidence that oxidized-LDL plays an important role in atherogenesis. We now report on the in vivo interaction between unfractionated heparin and oxidized LDL in rats. The recovery rates of the native LDL particles ranged between 75% and 85% of the injected dose. Heparin did not interfere with the clearance rates of native LDL. After administration of radioactive labeled oxidized-LDL particles, 26% of the material was measured in circulation after 5 minutes, 8% after 20 minutes, and 3% after 60 minutes. After injection of heparin 2 minutes prior to oxidized-LDL tracer particles, 44% of the tracer was found in blood after 5 minutes, 23% after 20 minutes, and 9% after 60 minutes. Oxidized-LDL tracer particles disappeared from blood with an alpha half-life of 5 minutes and a beta half-life of 7.5 minutes. After receptor blocking with unfractionated heparin the alpha half-life of the oxidized-LDL tracer was prolonged to 17.5 minutes and the beta half-life to 27.5 minutes. These results indicate that heparin molecules of a comparatively small molecular weight competed the scavenger receptor mediated uptake of oxidized-LDL particles in vivo. Oxidized-LDL particles are known to mediate their pro-atherosclerotic activity in part by stimulating smooth muscle cell proliferation by a scavenger receptor-mediated pathway. It can be speculated, if heparins interfere with the uptake of oxidized-LDL, heparins might thus in part exert their known antiatherosclerotic properties.

Animals↗
PubMed1995

Complexes of a modified low-molecular-weight heparin with protamine are predominantly cleared by a macrophage scavenger receptor-mediated process in rats.

Neutralization of heparin with its antidote protamine is associated with side effects such as pulmonary hypertension. The pharmacodynamic effects of protamine treatment are well documented. However, little is known about metabolic fate of heparin-protamine complexes. Twenty Wistar rats received a 131I-labeled low-molecular-weight heparin tracer intravenously. Four groups of animals were formed: a control group receiving the tracer, a second group receiving protamine after tracer application, a third group receiving maleylated bovine serum albumin (mal-BSA) prior to tracer and protamine injections to inhibit scavenger receptors of the reticuloendothelial system, and the last group receiving preformed heparin-protamine aggregates. All animals were examined by scintigraphy. Blood and tissue samples were analyzed for radioactivity. Protamine injection 2 min after heparin tracer application lead to a rapid decline in blood radioactivity. The radioactivity in the liver increased from 17% for the control to 43% after protamine application. Injection of mal-BSA prior to protamine prevented tracer accumulation in the liver and increased urine excretion (34% versus 20%). In vitro preformed heparin-protamine precipitates were rapidly trapped in the liver. We present evidence that, like the polyanionic heparin, polyanionic heparin-protamine complexes are phagocytosed by a scavenger receptor-mediated mechanism by macrophages, predominantly in the liver. The amount, the size, and the charge density of the complexes might trigger a mediator release from macrophages leading to phenomena such as pulmonary hypertension.

Animals↗
PubMed1995

Monitoring of heparins in haemodialysis using an anti-factor-Xa-specific whole-blood clotting assay.

In haemodialysis low-molecular-weight (LMW) heparin is increasingly used for anticoagulation. The advantages over unfractionated (UF) heparin are the lower bleeding risk and the lack of influence on lipid metabolism. However, no reliable and rapid method is available so far to control the efficacy and safety of LMW heparin during haemodialysis. The specific anti-factor Xa (aXa) chromogenic substrate assays are laborious and time consuming. In the present study we have compared chromogenic assay with a coagulation assay (heptest), which was performed from plasma and whole-blood samples. The effects were compared with unfractionated heparin during haemodialysis. The aXa activity in the chromogenic S2222 assay ranged between 0.2 and 0.5 U/ml with UF heparin and between 0.4 and 0.8 U/ml with LMW heparin during haemodialysis. The coagulometric aXa activity in heptest assay from plasma was 0.6-1.0 U/ml with UF heparin and 1.2-2.0 U/ml with LMW heparin. The Heptest coagulation values from citrated whole blood samples ranged from 0.4 to 0.8 U/ml with UF heparin and from 0.8 to 1.4 U/ml with LMW heparin. The prolongation of the heptest clotting times with UF and LMW heparin was in the range of 4.4 for UF heparin and 5.2 for LMW heparin using the whole-blood assay. Heptest assay from plasma samples yielded prolongations of 6.1 with UF heparin and 6.6 with LMW heparin. The data show that the coagulation assay is rapid and reproducible using plasma or uncentrifuged whole-blood samples and is valid to monitor UF heparin or LMW heparin in patients undergoing chronic intermittent haemodialysis.

Adult↗
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↗