Abstract:SummaryIn these investigations it was shown that the contact factors of the coagulation system - isolated as in the contact activation test according to Egli or as Celite eluate (Waaler) - do not influence platelet aggregation. Platelet aggregation was measured by the rotation method of Wright.It was concluded that contact of blood with wettable surfaces leads to activation of the coagulation system and independently to aggregation of platelets. By heating of plasma to 56° a platelet aggregating principle is l… Show more
“…Der gesamte Vorgang bedarf der Anwesenheit yon ADP, Calcium und eines hitzestabilen Plasmafaktors [4,23,89,91]. Der gesamte Vorgang bedarf der Anwesenheit yon ADP, Calcium und eines hitzestabilen Plasmafaktors [4,23,89,91].…”
Section: Die Aggregation Yon Thrombocytenunclassified
“…Diese lagern sieh zun/~ehst rever-sibel an die adh&renten Thrombocyten an, wozu Calcium und ein nieht genauer definierter, hitzestabiler Plasnafaktor nStig sind [4,23,89]. Es beginnt damit eine Reaktionskette, die zu morphologisehen Ver/~nderungen der P1/~ttehen, der viscSsen Metamorphose, fShrt.…”
Section: Die Aggregation Yon Thrombocytenunclassified
Biochemical Mechanisms in Inducing o/ Coagulation by Collagen. Summary. Collagen in the wall of blood vessels denuded by lesion of the endothelium activates clotting in two different ways: 1. by reaction with thrombocytes part of which adhere to collagen fibrils and initiate clumping of further platelets, 2. by activation of Hageman-Factor which induces the plasmatic clotting system to form a solid fibrin plug. These activation mechanisms depend on native collagen exhibiting a triple-helicM conformation of peptide chains. Adhesion of thrombocytes may be mediated by s-amino-groups of collagen as well as by incomplete carbohydrate groups attached to the side chains of certain hydroxylysine residues. Activation of Factor XII is promoted by free carboxylic groups of collagen and by the telopeptides. In this way different sites of the same molecule are responsible for the initiation of blood clotting by the two mechanisms. A synergism exists between them.
“…Der gesamte Vorgang bedarf der Anwesenheit yon ADP, Calcium und eines hitzestabilen Plasmafaktors [4,23,89,91]. Der gesamte Vorgang bedarf der Anwesenheit yon ADP, Calcium und eines hitzestabilen Plasmafaktors [4,23,89,91].…”
Section: Die Aggregation Yon Thrombocytenunclassified
“…Diese lagern sieh zun/~ehst rever-sibel an die adh&renten Thrombocyten an, wozu Calcium und ein nieht genauer definierter, hitzestabiler Plasnafaktor nStig sind [4,23,89]. Es beginnt damit eine Reaktionskette, die zu morphologisehen Ver/~nderungen der P1/~ttehen, der viscSsen Metamorphose, fShrt.…”
Section: Die Aggregation Yon Thrombocytenunclassified
Biochemical Mechanisms in Inducing o/ Coagulation by Collagen. Summary. Collagen in the wall of blood vessels denuded by lesion of the endothelium activates clotting in two different ways: 1. by reaction with thrombocytes part of which adhere to collagen fibrils and initiate clumping of further platelets, 2. by activation of Hageman-Factor which induces the plasmatic clotting system to form a solid fibrin plug. These activation mechanisms depend on native collagen exhibiting a triple-helicM conformation of peptide chains. Adhesion of thrombocytes may be mediated by s-amino-groups of collagen as well as by incomplete carbohydrate groups attached to the side chains of certain hydroxylysine residues. Activation of Factor XII is promoted by free carboxylic groups of collagen and by the telopeptides. In this way different sites of the same molecule are responsible for the initiation of blood clotting by the two mechanisms. A synergism exists between them.
“…Ein direkter Einflul~ der Kontaktfaktoren auf die Blutpl£ttchen lgBt sich in vitro mit Pliittehenaggregationstests nieht nachweisen (Barth et al, 1966), im Gegensatz zu der Wirkung eines isolierten bovinen Hageman-Faktors, der eine Pl~ttehenaggregationssteigerung verursachte (Mammen u. Grammens, 1967). Man mul~ also annehmen, dab die Aktivierung der Kontaktphase fiber die vermehrte Generation yon Thrombin die Thrombocytenverklumpung fSrdert.…”
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