Degradation of fibrinogen and cross-linked fibrin by human neutrophil elastase generates D-like fragments detected by ELISA but not latex D-dimer test.

Recently, we observed that D-dimers are degraded by human neutrophil elastase (HNE) into two D-like fragments, reacting with the monoclonal antibody in an ELISA D-dimer test but not reacting with the corresponding latex D-dimer test. To investigate this in more detail, we studied the degradation of cross-linked fibrin and fibrinogen by plasmin and HNE to see if this resulted in D-fragments or D-like fragments. Degradation of fibrinogen, both by plasmin and HNE, resulted in D- and D-like fragments, respectively, detected by the ELISA D-dimer test.

[Group learning in medical education].

The implementation of group learning in medical education puts special demands on the participants, but also offers pedagogical benefits, which may be conductive to the efficient learning of facts, skills and attitudes. The group makes it possible to verify or modify the learned material, which is an important part of preparing for a career as a doctor. Students develop a dependence on others when solving problems in groups, whereas as clinicians they are often alone when confronted with problems demanding quick decisions.

Discrepancy between latex and ELISA D-dimer values in sepsis may be caused by human neutrophil elastase.

We have recently shown that D-dimers are degraded by human neutrophil elastase (HNE) in vitro, causing rapid decrease in the D-dimer levels measured by a Latex test, but not with an ELISA test employing the same monoclonal antibody against D-dimer. To see if such discrepant D-dimer concentrations occurred in patients with high HNE concentration, we examined 80 plasma samples from 8 patients with sepsis with a Latex and an ELISA test and calculated the ratio between the D-dimer values obtained with the two tests. Twenty healthy pregnant and twenty pre-eclamptic patients, who are known to have raised D-dimer but low HNE concentrations, were chosen as controls.

D-dimers are degraded by human neutrophil elastase.

To see if D-dimers were degraded by human neutrophil elastase (HNE), cross-linked fibrin was obtained by adding thrombin to purified fibrinogen in the presence of calcium ions and factor XIII, and the fibrin clot subsequently degraded by plasmin. Thereafter, the supernatant containing fibrin degradation products was removed and incubated with HNE. D-dimer levels were measured by two rapid semiquantitative tests, a latex agglutination test and the Nycocard immunofiltration test, and a quantitative ELISA-method.