Fibrinogen and fibrinogen/fibrin degradation products in the urine of rabbits infected with Trypanosoma (Trypanozoon) brucei

Summary Studies have been carried out on the urine of rabbits infected with Trypanosoma (Trypanozoon) brucei to determine whether fibrinogen or fibrinogen/fibrin degradation products (FDP) could be detected. No fibrinogen was found but during the last two weeks of this 7-week infection low levels of FDP were present in the urine which did not exceed 5 g/ml. Rabbit urine was shown to contain a potent proteolytic enzyme capable of breaking down rabbit fibrinogen and both early and late FDP were present in the cleavage products. No deposits of fibrin were detected in the kidney, but casts were present in the urine suggesting renal damage. The most likely explanation of the urinary FDP is that either an increase in the glomerular permeability occurs allowing filtration of plasma FDP or a local fibrinogenolysis in the kidney tubules.     

Serum fibrin/fibrinogen degradation products as a prognostic index in acute myocardial infarction.

A study of the prognostic value of serum fibrin/fibrinogen degradation products (FDP) in 137 consecutive patients with acute myocardial infarction showed a positive correlation between high FDP levels and poor prognosis. Both the frequency of complications and the mortality were related to increased levels of FDP, the highest of which were found between the fourth and eighth days after infarction.     

Evaluation of two new assays for determination of serum fibrinogen/fibrin degradation products

Two new commercial assays for the detection of degradation products of fibrinogen/fibrin (FDP) were evaluated against two standard procedures. The first, a new hemagglutination inhibition (HAI) assay using glutaraldehyde-treated cells, was compared with the tanned red cell hemagglutination inhibition immunoassay (TRCHII). Analysis of 43 samples from patients with a variety of bleeding disorders and thrombotic conditions showed a high degree of correlation between methods (r = 0.934). The second new assay, a rapid slide test using antibody-coated latex particles, was compared with results obtained by electroimmunoassay. There were no significant differences in the results as assessed by two statistical parameters. It was concluded that both new tests are useful for routine use in clinical laboratories.     

Clinical significance of a new fibrinogen/fibrin degradation products(FDP) test using plasma samples for the diagnosis of fibrinogenolysis and fibrinolysis

Recently, a new fibrinogen/fibrin degradation products(FDP) test using monoclonal antibodies against FDP(LPIA FDP-P: FDP-P) has been developed, which is able to measure FDP directly in plasma. The objective of this study is to clarify clinical significance of the test in the diagnosis of fibrinogenolysis and fibrinolysis in comparison with a conventional FDP test using polyclonal antibodies against fibrinogen(FDP-S) and D-dimer test using monoclonal antibodies against D-dimer(D-D). The monoclonal antibodies used in FDP-P test was shown to recognize fragment X, Y and D1 derived from fibrinogen digested by urokinase, and was also to recognize XDP fragments, D-dimer and D derived from cross-linked fibrin digested by tissue plasminogen activator using SDS-PAGE and immunoblotting analysis. There was a good correlation of FDP levels between FDP-P test and FDP-S test. However, levels of FDP in both tests were discrepant in several samples. There was a tendency that the levels of FDP were higher in FDP-S test than in FDP-P test. Such discrepancy was suggesting that soluble fibrin monomer complex(FM) was recognized by the antibodies used in FDP-S test, but not recognized by the antibodies used in FDP-P test. There was also a good correlation of FDP levels between FDP-P test and D-D test. However, the levels of FDP in both tests were discrepant in several samples. The levels of FDP were higher in FDP-P test than in D-D test. These discrepant samples had lower levels of antiplasmin and higher levels of plasmin antiplasmin complex(PIC), and also showed XDP fragments, D-dimer, X, Y, and D1 by using SDS-PAGE. These observations suggest that D-D test measures only fibrinolytic fragments, while FDP-P test measures fibrinogenolytic fragments as well as fibrinolysis. In results, the FDP-P test was confirmed to be a useful tool to examine fibrinogenolysis as well as fibrinolysis more specifically than the conventional FDP test.     

The detection of fibrinogen/fibrin degradation products by means of a new antibody-coated latex particle

A rapid slide test for the detection of degradation products of fibrinogen/fibrin (FDP) using a new antibody-coated latex particle is described. The latex particle has been specifically coated with antibody to fragments D and E. The latex agglutination test (Thrombo-Wellcotest) has been compared with the tanned red cell haemagglutination inhibition immunoassay (TRCHII) in 143 patients with a variety of clinical conditions. There is a high degree of agreement between the methods with a coefficient of correlation of 0.83. The method provides a rapid, simple screening test for fibrin degradation products.     

Clinical evaluation of a test for plasma fibrin/fibrinogen degradation products (FDP) based on monoclonal anti-FDP antibody technology: an application for the scoring system of the disseminated intravascular coagulation (DIC) diagnostic criteria

Fibrin/fibrinogen degradation products(FDP) have been measured using serum samples which were specially prepared for the FDP test because of the usage of anti-human fibrinogen antibody for the assay. Since diagnostic criteria for DIC were established by the study group on thrombosis and hemostasis which is supported by the Japanese Ministry of Health and Welfare(JMHW), serum FDP assay have been used as standard methods to diagnose DIC in Japan. Recently, a reagent using an anti-human FDP monoclonal antibody was developed and this has enabled the use of plasma samples for FDP measurement. The comparability, especially of the DIC score, of a new assay, Latex test BL-2 P-FDP, using plasma samples with a conventional assay for serum was investigated. Two sets of DIC scores based on data from the two tests were compared and the correlation was high with 97.5% of the patients being diagnosed with the same DIC status. In four disease groups--DIC, thrombosis, leukemia and solid cancer--high comparability between the two tests was also shown and no significant difference was observed in the correlation coefficient and the slope coefficient between serum and plasma samples. To conclude, it is suggested that "Latex test BL-2 P-FDP" is applicable to the diagnostic criteria for DIC from JMHW without any difficulty.     

Conditions for collection of serum samples for the measurement of fibrin(ogen) degradation products by radioimmunoassay of fragment E.

A number of conditions have been assessed for the collection of serum samples for the measurement of fibrin(ogen) degradation products using a radioimmunoassay for degradation fragment E, which permits precise quantitation of differences. Blood should be collected using minimal venous occlusion into glass tubes containing 10 mg/ml of epsilon amino caproic acid and allowed to clot at 4 to 20 degrees C for at least 4 hours before centrifugation. The serum may be stored at 4 or -20 degrees C. Samples from patients receiving anticoagulant therapy should be treated with 10 IU of thrombin per ml.     

Comparison of tanned cell hemagglutination and counter immunoelectrophoresis test in the detection of antibodies to extractable nuclear antigens (ENA) and to DNA in the systemic lupus erythematosus

A comparative study of tanned cell hemagglutination (TCH) and counterimmunoelectrophoresis (CIE), two easy and reliable methodes for the routine detection of antibodies against nuclear antigens was performed. Antibodies against ENA, RNA-ase sensitive ENA and DNA antigens were searched in patients affected by systemic lupus erythematosus (SLE). Analysis of the results obtained for a particular antibody using TCH and CIE techniques suggests that both methods should be used for the detection of antibodies to nuclear antigens since in several cases antibodies were detected by one method and not for the other. Besides, the frequency of antibodies to ENA, RNA-ase sensitive ENA and DNA revealed by both techniques is similar to the results reported by others employing laborious tests. TCH and CIE serve as a screen to determine the presence of an antibody system and seems to provide the sensitivity enough as to be used in the smaller routine laboratories that wish to provide services for antibodies to nuclear antigens. When tanned cell hemagglutination was used looking for antibodies to DNA or ENA in the sera of patients affected by SLE it proved to be useful since in samples where antibodies to DNA were absent or at very low titres, antibodies to ENA were present in titres ranging from 1:9 to 1:6 561. The authors think this is of considerable importance since the variety of clinical features seen in different subjects with SLE is often accompanied by different specificities or types and amounts of autoantibodies and that certain combinations of these antibodies coincide with specific clinicopathological abnormalities.     

Enzyme immunoassay for feline oncornavirus-associated cell membrane antigen (FOCMA) and detection of FOCMA in cell extract by enzyme immunoassay inhibition test.

An enzyme immunoassay (EIA) for FOCMA has been developed. The assay uses alkaline phosphatase-conjugated rabbit anti-cat IgG as the second antibody and p-nitrophenyl phosphate as the substrate for the enzyme to detect cat FOCMA antibody bound to the target cells. In comparison with the indirect immunofluorescence (IIF) test, which was originally used for FOCMA assay, our results showed a good correlation between the two methods. The EIA gives a more objective measure of FOCMA reactivity than does IIF. FOCMA was successfully extracted from FOCMA-positive cell membranes by 0.5% Triton X-100 and further fractionated by ammonium sulfate. The FOCMA activity was assayed by IIF and EIA inhibition test. Most of the FOCMA activity was found in the fractions precipitated by 30% and 50% ammonium sulfate saturation.     

Prevalence and clinical implications of heparin-associated false positive tests for serum fibrin(ogen) degradation products

An electrophoretic method has been applied to characterize specific fibrinogen and fibrin degradation products (FDP) in 135 serum samples from 59 consecutive patients having a positive latex agglutination test for serum FDP in the evaluation of consumption coagulopathy. In 20 of 135 positive samples, the principal fibrinogen derivatives present were not degradation products of fibrinogen or fibrin but were instead residual fibrinogen or fibrin monomer and polymers (FFMP) due to incomplete clotting. Heparin exposure was common in patients with positive FDP tests occurring in 29 of 59 patients (49%) with 81 of 135 samples (60%). Heparin exposure by parenteral administration or catheter was significantly correlated with a false positive serum FDP test because of residual FFMP occurring in 19 of 81 (23%) samples from heparin-exposed patients but in only 1 of 54 (2%) samples from patients without exposure (P less than 0.005). Treatment of the false positive samples with reptilase, an enzyme unaffected by heparin, resulted in complete removal of the residual FFMP, and in vitro experiments demonstrated that heparin-containing plasma samples could be completely clotted with either reptilase or protamine sulfate plus thrombin. Survey of 20 regional laboratories showed that only 10% used reptilase or protamine sulfate to prepare serum if heparin exposure had occurred and that this was done in only 22 of 5,049 (0.4%) of samples in the last calendar year. Greater attention should be given to proper preparation of serum from heparin-exposed patients, and physicians should be aware of the possibility of falsely positive or falsely elevated serum FDP tests in evaluation of consumption coagulopathy in heparin-exposed patients.     

Comparison of an enzyme-linked immunoassay with an indirect hemagglutination assay for the detection of antibodies to cytomegalovirus

Because of the morbidity associated with cytomegalovirus (CMV) infections in neonates, immunosuppressed and transplant patients, there is a need for a rapid, sensitive, and reliable assay for the presence of antibody to CMV. Such an assay would permit the identification of CMV antibody negative blood or plasma for transfusion into these high-risk patients. The indirect hemagglutination assay (IHA) is often employed to detect antibodies to CMV, but results must be interpreted subjectively. Thus, an indirect enzyme immunoassay (EIA) was developed to detect antibodies to CMV, and was compared to IHA. 531 sera from a population of healthy blood donors were assayed by both methods. Compared with IHA the sensitivity of the indirect EIA was 98.5% (267/271) and the specificity was 93.1% (242/260). Antibodies to Epstein-Barr, herpes-zoster, or herpes simplex viruses did not react in the EIA. The EIA and IHA correlated well in the detection of antibodies to CMV in sera from acute CMV infections. The presence of rheumatoid factor did not interfere with the EIA or IHA results. This indirect EIA is a rapid, simple, and reproducible method to identify seronegative sera or plasma.     

Comparison of a direct antigen enzyme immunoassay, Herpchek, with cell culture for detection of herpes simplex virus from clinical specimens.

Direct enzyme immunoassay (Herpchek) was compared with culture on 21,522 specimens mainly from asymptomatic women for herpes simplex virus detection. Sensitivity and specificity were 73.8 and 97.7%, respectively. The 33% detection rate by enzyme immunoassay in 5 h increased to 43% when the enzyme immunoassay was combined with culture. Herpchek alone was not sensitive enough, but in combination with culture, maximum detection was achieved.