RESUMEN
After venous occlusion (VO), D-dimer levels were measured by means of an ELISA technique, in citrated plasma clotted by thrombin and in serum from whole blood. D-dimer levels increased with duration of incubation (30 min to 24 hours). D-dimer values, both in clotted plasma and in serum (n = 12), incubated 4 hours at room temperature, correlated well with euglobulin clot lysis time (ECLT) (r = -0.85 and -0.89, respectively, p less than 0.002) and tissue plasminogen activator (t-PA) activity, (r = 0.82 and 0.83, respectively, p less than 0.002). D-dimer concentrations from plasma and serum (n = 25) were compared (r = 0.90, p less than 0.001). Healthy volunteers (n = 65) were tested to establish reference values in serum from post-occlusive whole blood samples incubated 4 hours prior to centrifugation. Finally, a patient group (n = 62) was examined. For the whole material (n = 152) such D-dimer concentrations correlated well with both ECLT (r = -0.85, p less than 0.001) and t-PA activity (r = 0.81, p less than 0.001). D-dimer levels in serum were determined by a latex agglutination test as well. These semi-quantitative values also correlated significantly with both ECLT (r = -0.86, p less than 0.001) and t-PA activity (r = 0.87, p less than 0.001). We conclude that measurement of D-dimer as described above, represents a simple and accurate method for assessment of global fibrinolytic activity following VO. The latex agglutination test is particularly suitable as a screening procedure.
Asunto(s)
Productos de Degradación de Fibrina-Fibrinógeno/análisis , Fibrinólisis , Tromboflebitis/sangre , Venas , Adolescente , Adulto , Anciano , Constricción , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Pruebas de Fijación de Látex , Masculino , Persona de Mediana Edad , Tromboflebitis/tratamiento farmacológico , Activador de Tejido Plasminógeno/análisis , Warfarina/uso terapéuticoRESUMEN
The influence of pH on heat denaturation of anti-haemophilic cryoprecipitate (CP) was studied by using phosphate and citrate buffers at three different pH levels for processing lyophilized, heat treated CP. The solubility and the content of FVIII:C and fibrinogen were determined following heating at 68 degrees C for 24 hours and compared to "ordinary", non-heated CP. Both the solubility and the biological activity were best preserved in the most acidic samples (pH 5.7-6.7), these batches equalled non-heated CP. At higher pH, heat treatment resulted in reduced solubility and a more pronounced loss of FVIII:C and fibrinogen. Amino acids (Syntamin 17) have previously been shown to stabilize CP during heat treatment. Some of the stabilizing effect seems to be due to a large buffering capacity, maintaining a low pH during lyophilization and heating. Raising the pH level in Syntamin-CP from 6.6 to 7.8 resulted in decreased solubility and FVIII:C content. The quality of heat treated, acidic Syntamin-CP was comparable to that of heated, acidic phosphate- and citrate-CP. We conclude that buffers used for processing heat treated CP should be of low pH, and that acidic buffers may replace Syntamin without lowering the quality of the heated product.