Determination Of Fibrin Degradation Products Research Articles

Comparison of diverse platelet activation markers as indicators for left atrial thrombus in atrial fibrillation

Atrial fibrillation (AF) is well known for being a major risk factor of thromboembolic stroke. We could recently demonstrate an association of monocyte–platelet aggregates (MPAs) with the degree of thrombogenicity in patients with AF. This study investigated platelet activation markers, as potential biomarkers for the presence of left atrial (LA) thrombus in patients with AF. One hundred and eight patients with symptomatic AF underwent transesophageal echocardiography (TEE) before scheduled cardioversion or pulmonary vein isolation. In order to determine the content of MPAs by flow-cytometric quantification analyses, blood was drawn on the day of TEE. The soluble CD40 Ligand (sCD40L) and soluble P-selectin (sP-selectin) were obtained by Cytometric Bead Arrays (CBA). D-dimer levels were detected by quantitative immunological determination of fibrin degradation products. Clinical, laboratory, and echocardiographic standard parameters were obtained from all patients, including the determination of the flow in the left atrial appendage (LAA). Patients with detected LA thrombus (n = 28) compared with patients without thrombus (n = 80) showed an increased number of common risk factors, such as age, diabetes, heart failure, and coronary artery disease (CAD). The presence of LA thrombus was associated with significantly increased levels of MPAs (147 ± 12 vs. 304 ± 29 per µl; p < 0.00), sCD40L (106.3 ± 31.0 vs. 33.5 ± 2.1 pg/ml, p = 0.027), and D-dimer (0.13 ± 0.02 vs. 0.69 ± 0.21 mg FEU/l, p = 0.015). In contrast, sP-selectin showed no association with LA thrombus. A multivariate regression analysis showed that MPAs, sCD40L as well as D-dimers were independent indicators for the existence of LA thrombus. MPAs above 170 cells/µl indicated LA thrombus with a high sensitivity of 93% and a specificity of 73% (OR 62, 95% CI. 6.9–557.2, p < 0.001) in patients with AF, whereas the D-dimer lost their quality as independent indicator by using the conventional cut-off of 0.5 mg/l within the regression analysis. MPAs, as well as the D-dimer, correlated significantly negatively with the flow in the LAA measured during TEE. The content of MPAs, sCD40L, and D-dimer, but not sP-selectin showed an increased dependence on LA thrombus in patients with AF. In our study group, MPAs showed the best diagnostic test accuracy of the compared platelet markers. The different results of the examined platelet activation markers could be an indication of diverse mechanisms of LA thrombus in AF. Further studies should evaluate whether determination of MPAs in clinical routine may suffice to indicate the presence of LA thrombus in patients with AF.

Ovarian Carcinoma: Clinical Validity by Simultaneous Determination of Fibrin Degradation Products with the DR-70™ Immunoassay and CA-125

Fragestellung: Tumorzellen weisen häufig einen hohen Gehalt an Proteasen auf, die entscheidend an der Fibrinolyse beteiligt sind. Der DR-70™-Immunoassay misst mit hoher Spezifität Degradationsprodukte des Fibrins. Dieser Test ist, wenn auch an kleinen Fallzahlen, erfolgreich eingesetzt worden als Tumormarker zur Erfassung einer Reihe von Tumorentitäten. In der vorliegenden Arbeit wird dieser Test beim Ovarialkarzinom mit CA-125, dem „Goldstandard“ beim Ovarialkarzinom, verglichen. Methoden: Im Serum von 61 Patientinnen mit histologisch gesichertem Ovarialkarzinom, aber auch im Serum von 135 Patientinnen mit entzündlichen Erkrankungen bzw. anderen Malignomen bzw. benignen Tumorerkrankungen wurde die Aktivität von DR-70™ im Serum gemessen. Als Kontrollgruppe dienten 100 Blutspenderinnen, die als tumorfreie, gesunde Frauen eingestuft wurden. Der DR-70™ ist ein ELISA, der nach den Vorgaben des Herstellers (AMDL, Tustin, CA, USA) eingesetzt wurde. Ergebnisse: Als Mittelwert ± S. D. in der Kontrollgruppe wurde 0,41 ± 0,1 µg/ml für DR-70™ ermittelt. Im Vergleich dazu lag der Mittelwert der Serumproben von 61 Patientinnen mit Ovarialkarzinom bei 7,0 ± 10,5 µg/ml, bei einer Schwankungsbreite von 0,6 bis 58,5 µg/ml. Wird der Cut-off-Wert für DR-70™ auf > 1,2 µg/ml festgelegt, beträgt die Sensitivität des Testes 83,6 %, und der Wert für die Spezifität liegt bei 100 %. Verglichen mit CA-125 liegt die Sensitivität für DR-70™ 13,1 % höher. Schlussfolgerung: DR-70™ repräsentiert einen Tumormarker, der mit höherer Sensitivität und vergleichbarer Spezifität wie CA-125 Ovarialkarzinome zu diagnostizieren in der Lage ist.

Determination of fibrin degradation products by ELISA

Determination of fibrin degradation products by ELISA

Determination of fdp in human plasma by a novel latex immunoassay

Distribution analyzing latex immunoassay (DALLA), a sensitive method based on the agglutination of latex particles coated with monoclonal antibody, was developed for determination of fibrin degradation products (FDP) in human plasma. The agglutination is measured by using an electric particle counter designed for medical research to determine the volume-ratio of agglutinated to non-agglutinated particles. Interference by serum constituents is avoided by coating the particles with the F(ab')e fragments of monoclonal antibody and by using suitable latex particles. This assay enabled the determination of FOP in concentrations of 16 to 4000 ng/ml in less than 15 minutes. The mean concentrations of FDP in the plasma of 98 normal subjects and 142 patients with apparent disseminated intravascular coagulation (DIC) were 0.69 and 13.24 g g/ml, respectively. Analytical recovery of FDP in plasma samples averaged 104%. The correlation coefficient of DALLA with enzyme immunoassay using two monoclonal antibodies, was 0.809. The results obtained by analyzing the cross-reactivity with related components of FDP and the inhibitory effect of D monomer indicated that the present method can effectively detect the high molecular weight (HMW) fragments of FDP produced in the early stage of plasmin digestion.

207 New methods for immunological determination of fibrin degradation products

207 New methods for immunological determination of fibrin degradation products

The fibrinolytic activity of cerebrospinal fluid after subarachnoid hemorrhage.

Fibrinolytic activity of cerebrospinal fluid and peripheral blood was studied in 14 patients with subarachnoid hemorrhage during the high-risk period of subarachnoid rebleeding. Fibrinolytic activity of cerebrospinal fluid or peripheral blood could not be demonstrated. Determination of fibrin degradation products showed high levels in cerebrospinal fluid, being a result of meningeal irritation. The findings in this study--as well as other observations--suggest, that antifibrinolytic therapy should not be administered in patients with subarachnoid hemorrhage.

An experimental model of in vivo fibrinolysis

An experimental model of in vivo fibrinolysis was devised for estimation of in vivo fibrinolytic activity in experimental animals (rat, rabbit and dog). The method consists of intravenous injection of homogenized human fibrin into an animal and subsequent immunological determination of fibrin degradation products (FDP) in a small amount of serum from the animal with the use of a commercial FDP kit for clinical use. In experiments with rats, FDP production was significantly increased by an injection of the fibrinolytic agent bisobrin while it was inhibited by treatment with the anti-fibrinolytic agent tranexamic acid (AMCA). These effects were in parallel with the effects of these agents on the euglobulin clot lysis time (ELT) determined in plasma samples from the treated rats. In vivo fibrinogenolysis could also be measured by this method if human fibrinogen was used in place of human fibrin. Fibrinogenolysis was not observed in untreated rats, but it was observed in rats treated with bisobrin.

The early diagnosis of gram negative septicemia in the pediatric surgical patient.

Ninety-three postoperative patients 1 day to 13 years of age had blood cultures, limulus lysate assay, determination of fibrin degradation products, white blood cell and platelet counts. Seven groups were studied. The limulus lysate assay was often positive (64%) in the presence of gram negative septicemia but there were false positives and negatives. The tests for fibrin degradation products were inconsistent. The white blood cell count was low in babies with gram negative septicemia. One hundred per cent of the infants with gram negative septicemia had a platelet count below 150,000; 71% below 100,000 (average 67,000 septic babies, 257,000 non-septic babies). The drop in platelet count with gram negative septicemia was abrupt---as much as 222,000 in 24 hours. Platelets increased when therapy was effective. Two children with gram negative septicemia had platelet counts of 50,000 and 20,000. The platelet count for patients with gram positive septicemia was 299,000, and above 150,000 in all children with ruptured and non-ruptured appendicitis and major surgery without gram negative septicemia. It was concluded that serial measurements of platelet count in the postoperative infant and child was a rapid and reliable method for early detection of gram negative septicemia and changes in platelet count in response to treatment was an indicator of the effectiveness of therapy.

A simple passive hemagglutination-inhibition technic for determination of fibrin degradation products and fibrinogen.

A simple method for determination of fibrin degradation products and fibrinogen was sought. A mixture of 0.1 ml. packed human O cells, 1.2 ml. of citrate buffer, pH 6.2, 0.5 mg. of BSA, 0.1 mg. of fibrinogen, and 0.25 ml. of 2.5% glutaraldehyde was rotated for two hours at room temperature and the coating of O cells with fibrinogen was accomplished. Hemagglutination of the preparation by antifibrinogen was readily inhibited by fibrin degradation products and fibrinogen and was successfully used for their determinations. BSA coated on human O cells served as a good stabilizer. The technic bypassed the tanning process and the absorption of heterophil antibody.

Increased fibrinolytic activity and fibrin degradation products after experimental intracerebral haemorrhage.

The fibrinolytic activity of the peripheral blood and cerebrospinal fluid was studied in 10 dogs in which intracerebral haematomas had been produced by injection of blood into the brain. Blood and cerebrospinal fluid samples were obtained at regular intervals before and after operation. The fibrinolytic activity of these two fluids were estimated by the fibrin plate method and by assays for fibrin degradation products. After the production of the haematoma, signs of increased fibrinolytic activity were found in blood and cerebrospinal fluid one day after the intracerebral injection in 6 animals. A correlation was found between the size of the haematoma and the level of the fibrinolytic activity of blood and cerebrospinal fluid. Determination of fibrin degradation products in blood and cerebrospinal fluid and the measurement of fibrinolytic activity by the plate method complement each other and are therefore recommended in this type of investigation.