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Biomedical subjects

E Vahtera

Publications and source records attributed to E Vahtera.

42 records · Page 3Linked to original sources
PubMed1978

Interaction of urokinase with alpha2-macroglobulin investigated by isoelectric focusing. Evidence for non-specific dissociable binding.

The binding of urokinase to human alpha2M (alpha2-macroglobulin) was investigated in comparison with the formation of the equimolar trypsin-alpha2M complex. Experiments were performed by molecular-sieving on Sephadex G-200, subunit conversion by sodium dodecyl sulphate-polyacrylamide-gel electrophoresis after reduction and isoelectric focusing in linear sucrose gradients with ampholytes pH 3.5-10.0. Urokinase activity was determined with alpha-N-acetyl-L-lysine methyl ester and by activation of plasminogen on unheated fibrin plates. alpha2M was determined by single radial immunodiffusion. alpha2M was capable of binding some urokinase by a non-specific type of attachment that could be disrupted by isoelectric focusing but not by gel filtration. The pI of the undissociated trypsin-alpha2M complex was 6.0, and differed from that of the pure alpha2M (5.2-5.4). Likewise the pI of the immunoreactive alpha2M was 5.2 after exposure to urokinase, whereas the dissociated urokinase focused at pI 10.2. This indicated lack of true inhibitor-complex formation, which was also sustained by total absence of subunit conversion. The results are in agreement with our previous findings with pancreatic and urinary kallikreins.

Endopeptidases↗
PubMed1976

Absence of binding of pancreatic and urinary kallikreins to alpha 2-macroglobulin.

Pancreatic and urinary kallikreins failed to form the typical serine proteinase complex with alpha2M (alpha2-macroglobulin). Studies were performed to compare this with the binding of trypsin to alpha2M at various molar binding ratios, with the use of Sephadex G-200 gel filtration to separate free and alpha2M-bound enzyme fractions. The subunit conversion was totally absent with pancreatic kallikrein from lhich traces of a binding proteinase had been removed. The lack of binding is believed to be the result of the restricted specificity of the kallikreins.

Chemical Phenomena↗
PubMedDate not supplied

Fibrinolysis after application of a pneumatic tourniquet.

The fibrinolytic system was studied after application of a pneumatic tourniquet in 22 patients undergoing elective orthopaedic surgery and during 20-min venous occlusion in 17 healthy subjects. Blood was sampled before anaesthesia (A), before operation (B) and after operation from the ipsilateral (C) and the contralateral (D) limb. Tissue plasminogen activator (t-PA) activity, t-PA antigen and t-PA activity/t-PA antigen ratio increased by, respectively, 557, 109 and 168% in the C samples as compared with A blood (all differences statistically significant). The t-PA activity and t-PA antigen increased slightly in the systemic circulation (B and D) but were significantly less in C than after venous occlusion. Fast-acting inhibitor of t-PA increased significantly in C (15%). During compression with a pneumatic tourniquet, mainly local fibrinolytic activation occurs, and this activation partly explains the low incidence of postoperative deep venous thrombosis after use of a tourniquet.

Adult↗