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Biomedical subjects

N Egberg

Publications and source records attributed to N Egberg.

At least 91 records · Page 5Linked to original sources
PubMed1983

Assay for Hageman factor (factor XII) in human plasma by means of chromogenic substrate for plasma kallikrein.

Determination of factor XII was performed in a test system where plasma samples were diluted (1/400-1/3200) in buffer and factor XII deficient plasma. Diluted CephotestR was used as activator and after 10 min activation time chromogenic substrate H-D-Pro-Phe-Arg-pNA was added. The assay was adopted to an enzyme analyzer. The reproducibility of the method was acceptable with a coefficient of variation of 7.8% in the normal range. The correlation of this method to a one-stage clotting assay for factor XII was good, r 0.79. The preliminary reference interval was calculated to be 52-147% of normal (mean+ 2 S.D.).

Chromogenic Compounds↗
PubMed1983

Fibrinolytic and coagulation mechanisms in stages of inflammation: a study of BCG-induced pleural exudate in guinea pig.

Pleural fluid from an early, active phase of BCG-induced pleurisy was compared with fluid from late, healing phase, characterized by fibrinous adhesions. Exudates were tested for proteolytic activity on chromogenic peptide substrates designed for plasmin, tissue plasminogen activator, factor Xa, thrombin and plasma kallikrein. Considerable activity of active-phase pleural fluid was found on all of these substrates, and significantly lower values in the healing phase. Most exudates from both stages had very low fibrinogen concentration. Fibrinopeptide A, fibrinolytic products and antiplasmin were found in all exudates. Little or no fibrinolytic effect of pleural fluid was demonstrable on plasminogen free fibrin plates, despite the high activities on the low molecular weight substrates. Occurrence of alpha 2-macroglobulin-enzyme complexes is suggested as an explanation. The experimental results indicate that protease of the fibrinolytic and coagulation systems are active in the chronic inflammation of pleurisy, with higher levels of activity in active pleurisy phase.

Animals↗
PubMed1982

A study of hemostasis in ischemic cerebrovascular disease. II. Abnormalities in platelet ADP release, platelet cyclooxygenase regeneration time and platelet factor 3 availability.

Most earlier studies of platelet function in stroke patients have been performed in the acute phase and are hampered by diagnostic insecurity. A sample of totally 67 young adults below the age of 55, with ischemic cerebrovascular disease (TIA and minor stroke) were investigated at a late stage after acute disease and compared to 20 healthy controls. Patients with atherosclerotic signs at cerebral angiography had significantly (p less than 0.05) higher platelet factor 3 availability than angionegative patients. Unexpectedly, female patients compared to male patients had significantly (p less than 0.05) larger ADP-release after stimulation with collagen in vitro. Furthermore, when female patients were compared to female controls a significantly (p less than 0.05) increased platelet factor 3 availability was found. The results indicate that platelets in female patients may have an increased tendency to aggregate in vivo. Patients had significantly (p less than 0.01) shortened platelet cyclooxygenase regeneration half times (PRT). This was correlated to high levels of factor VIII related antigen (r=0.59) and high levels of factor VIII biological activity (r=0.67), indicating that platelets may be consumed by platelet adhesion and mural thrombi formation in abnormal vessel walls. PRT appears to be a reliable method to assess platelet function in vivo and to optimize aspirin dose and dose intervals in the individual.

Adenosine Diphosphate↗
PubMed1982

A study of hemostasis in ischemic cerebrovascular disease. III. Abnormalities in vascular plasminogen activators, antiactivators and alpha 2-antiplasmin.

A sample of in all 119 patients with ischemic cerebrovascular disease (TIA and minor stroke) below the age of 55 years, were submitted for testing of fibrinolysis in the late recovery phase after acute disease. Defective fibrinolysis, as tested after venous stasis, was found in patients (p less than 0.01) as compared to controls using a conventional fibrin plate method. A new chromogenic peptide substrate method showed a similar tendency. Antiactivator activity, measured as antiurokinase, using a peptide substrate, was significantly higher (p less than 0.01) in young female patients than in female controls. Alpha 2-antiplasmin (peptide substrate method) was significantly (p less than 0.001) higher in female than male patients. However, no correlation was found between inhibitors of fibrinolysis and defective fibrinolysis after venous occlusion. Furthermore, in a pilot study of vein biopsies, normal content of vascular plasminogen activators was found in the majority of cases. Thus, it is suggested that defective fibrinolysis in most cases reflects a disturbed release function.

Adolescent↗
PubMed1981

High frequency of low plasma haptoglobin values found in hemophilia A patients on prophylactic treatment with factor VIII concentrates - a sign of hemolysis?

Low plasma haptoglobin values have been observed in hemophilia A patients on regular prophylactic treatment with factor VIII concentrates. Two of 3 patients treated with fraction I-0 (Kabi) and 7 of 11 patients treated with high-purity concentrates (Hyland) had low haptoglobin values. Four of 8 patients who were treated with high-purity concentrates prescreened for a low content of anti-A and anti-B immunoglobulins still showed low haptoglobin levels. Unexpectedly, 2 patients of blood group 0 showed low haptoglobin values. The presence of irregular erythrocyte alloantibodies and/or other contaminants of the concentrates might thus also be a cause of hemolysis resulting in an increased consumption of haptoglobin. Elevated lactate dehydrogenase levels were also frequent. No correlations were found between albumin, aspartate or alanine aminotransferase levels and haptoglobin levels.

Adolescent↗
PubMed1978

Studies on assays for plasma prekallikrein and for the monitoring of coumarol therapy.

Chromogenic substrates were used to assay prekallikrein, prothrombin and factor X. Plasma prekallikrein was contact activated and allowed the splitting of HD-Pro-Phe-Arg-PNA which has affinity for plasma kallikrein. Prothrombin was assayed in various ways (immunologically, after activation with Ecarin or in a less specific way). Determination of factor X is considered as a possible specific method in the monitoring of coumarol therapy.

Coumarins↗
PubMed1977

Fasting (acute energy deprivation) in man: effect on blood coagulation and fibrinolysis.

Blood coagulation and fibrinolysis parameters were studied during 10 days of total fasting in healthy, normal weight males. A reduction of plasma levels of factor VIII activity with a concomitant decrease in factor VIII antigen was found, without other laboratory evidence for a disseminated intravascular coagulation. The effect of 10 days' starvation on blood coagulation appears to be small but the effect of more prolonged starvation might implicate impaired hemostasis.

Adult↗