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U Hedner

Publications and source records attributed to U Hedner.

224 records · Page 13Linked to original sources
PubMedDate not supplied

Shelf-life of bank blood and stored plasma with special reference to coagulation factors.

Whole blood and plasma drawn into plastic bags containing citrate-phosphate-dextrose (CPD) and stored at 4 degrees C for various periods were studied for variations of coagulation factor and fibrinolytic activity. The blood was collected and processed in the conventional way. The most labile component, factor VIII coagulant activity, decreased to about 50 percent of its original value within the first 24 hours in whole blood, but thereafter, it decreased more slowly. Storage of whole blood for 6 hours at 4 degrees C had an insignificant effect on VIII coagulant activity; an even slower decrease was found for factor VIII coagulant antigen. The major fall in VIII coagulant activity occurred between 6 and 24 hours of whole blood storage. Factor VIII-related antigen remained normal for about 1 week, but on further storage showed signs of proteolytic degradation. In plasma, there was a successive decrease in VIII coagulant activity with its minimum level (about 50% decrease as compared with the original level) after 7 to 14 days of storage. All other factor VIII activities in plasma remained unchanged throughout the study. Factor V retained its activity for about 1 week in the whole blood. Factors II, VII, IX, X, XII, XIII and fibrinogen did not fall below normal during a storage period of 35 days, nor was there any indication of increased fibrinolytic activity in either whole blood or plasma. Storage of whole blood and plasma at 4 degrees C for 1 to 2 weeks seems to have relatively little effect on the levels and function of various coagulation components with the possible exception of factor VIII coagulant activity.

Antigens↗
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Phenformin and ethyloestrenol in recurrent venous thrombosis.

Altogether 75 patients, 60 of whom had recurrent idiopathic deep venous thrombosis, 10 recurrent superficial thrombophlebitis and 5 retinal venous thrombosis, were given a combination of 100 mg phenformin and 8 mg ethyloestrenol a day for periods varying between 3 and 48 months (mean 16.2). Initially, all the patients had an abnormally low plasminogen activator content in the walls of superficial veins and/or a decreased capacity to release plasminogen activator from the vein walls on venous occlusion of the arms. The combination elicited a significant increase in the spontaneous fibrinolytic activity and in the local fibrinolytic activity during standardized venous occlusion of the arms (assayed on fibrin plates) after treatment for 3 months (p less than 0.001). These activities then remained normal throughout the observation period. In 65 of the 75 patients studied, the plasminogen activator level in the vein wall (histochemically assayed by the method of Pandolfi) was abnormally low intitially. The level had increased significantly after treatment for 3 months (p less than 0.001). After treatment for 12 months all the patients except 2 were normal. The patients in this material had had 2-20 episodes of venous thrombosis, the most recent 5 years before the institution of treatment, in spite of dicoumarol treatment. During treatment 9 thrombotic episodes occurred; in 5 of these patients the fibrinolytic activity of the vessel wall was not normal at the time of the recurrence. Except in 1 patient, who developed lactic acidosis, the side-effects were not severe.

Adolescent↗
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Does glycosylation influence the experimental antithrombotic effect of a two-domain tissue factor pathway inhibitor?

We have earlier shown that both full-length and truncated glycosylated tissue factor pathway inhibitor (TFPI) lacking the third Kunitz domain and the c-terminal region has an antithrombotic effect comparable to lowmolecular-weight heparin (LMWH) in an experimental venous thrombosis model. The aim of this study was to investigate whether a recombinant truncated non-glycosylated TFPI (117QTFPI1-161) had an antithrombotic effect similar to the glycosylated TFPI1-161 and LMWH. We also followed the coagulation parameters. The thrombi were induced in rabbit jugular veins with a combination of endothelium destruction and restricted blood flow. Group 1: placebo; group 2: LMWH 60 anti-Xa IU/kg, i.v.; groups 3 and 4: TFPI1-161 0.8 and 0.2 mg/kg, i.v., respectively; groups 5 and 6: 0.8 and 0.2 mg/kg 117QTFPI1-161, i.v., respectively, in a randomized double-dummy fashion. Twelve animals were included in the placebo group and 6 in each of the other groups. The frequency of thrombosis and also of occlusive thrombosis was reduced in all groups compared to placebo. The thrombus weight was reduced (0-9.9 mg) in all groups, significantly in groups 2, 4 and 5 (p = 0.004-0.02) compared to placebo (21.1 mg). In group 3, a borderline p value was achieved (0.06 likely a beta-error). The two forms of TFPI1-161 given in the higher doses showed a significantly greater increase of anti-Xa activity, but with a shorter duration compared to LMWH (1.7-1.9 vs. 0.9 anti-Xa IU/ml). Activated partial thromboplastin time (aPTT)-analysis revealed that only LMWH (52 s) caused a significant transient elevation 2 min after injection. In the other groups, a temporary but insignificant elevation of aPTT (27-37 s) was seen. No detectable effect on anti-IIa activity and prothrombin time (PT) was seen in any TFPI group. The glycosylation of the second domain on TFPI does not substantially contribute to the antithrombotic effect of TFPI. Regardless of the glycosylation of TFPI1-161, it has a dose-dependent effect on anti-Xa, a small effect on the aPTT, but no effect on anti-Ila and PT. LMWH has a more pronounced and sustained impact on these parameters.

Animals↗
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Low molecular weight heparin compared with dextran as prophylaxis against thrombosis after total hip replacement.

The effect of low molecular weight (LMW) heparin given once daily as prophylaxis against venous thrombosis was compared with that of dextran 70 in an open randomised trial of 100 patients undergoing elective total hip replacement. Four patients were withdrawn after randomisation and thus 96 were included in the final analysis. The development of thrombus was surveilled by the 125I fibrinogen test, and positive readings were verified by venography. Nine of 47 patients given LMW heparin developed thromboses (19%) compared with 18 of 49 given dextran (37%) (p = 0.09). Two further patients who received LMW heparin developed thromboses after leaving hospital (clinical signs became apparent on days 13 and 17, respectively), giving an overall rate of thrombosis in this group of 23%. Minor wound haematomas occurred in two of 47 in the LMW heparin group and three of 49 in the dextran group (4% and 6%, respectively), and blood loss, transfusion requirements, and reduction in postoperative haemoglobin concentration did not differ between the two groups. The studied LMW heparin given subcutaneously once a day was no less safe or effective than dextran in preventing thromboembolism after total hip replacement.

Aged↗