Thromboplastic Activity of Red Cells

SummaryThe composition of the occlusive material within dilated glomerular capillaries, following intravenous injections of Liquoid in blue foxes, was studied electron microscopically; it was found that it mainly consisted of a debris in which disintegrated red cells constituted the major component. Damaged platelets and necrotic endothelial remnants were other components. These observations were interpreted as a result of glomerular stasis, and it was concluded that stasis in glomerular capillaries is a basic event in the development of the renal lesions accompanying the generalized Shwartzman reaction.

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Receptor Mediated Binding of the Fibrinolytic Components, Plasminogen and Urokinase, to Peripheral Blood Cells

Thrombosis and Haemostasis ◽

10.1055/s-0038-1646019 ◽

1987 ◽

Vol 58 (03) ◽

pp. 936-942 ◽

Cited By ~ 96

Author(s):

Lindsey A Miles ◽

Edward F Plow

Keyword(s):

T Cells ◽

B Cell ◽

Peripheral Blood ◽

Binding Sites ◽

Blood Cells ◽

High Capacity ◽

Red Cells ◽

Peripheral Blood Cells ◽

Cellular Functions ◽

Fibrinolytic Proteins

SummaryGlu-plasminogen binds to platelets; the monocytoid line, U937, and the human fetal fibroblast line, GM1380 bind both plasminogen and its activator, urokinase. This study assesses the interaction of these fibrinolytic proteins with circulating human blood cells. Plasminogen bound minimally to red cells but bound saturably and reversibly to monocytes, granulocytes and lymphocytes with apparent Kd values of 0.9-1.4 μM. The interactions were of high capacity with 1.6 to 49 × 105 sites/cell and involved the lysine binding sites of plasminogen. Both T cells and non-rosetting lymphocytes and two B cell lines saturably bound plasminogen. Urokinase bound saturably to gianulocytes, monocytes, non-rosetting lymphocytes and a B cell line, but minimally to T cells, platelets and red cells. Therefore, plasminogen binding sites of high capacity, of similar affinities, and with common recognition specificities are expressed by many peripheral blood cells. Urokinase receptors are also widely distributed, but less so than plasminogen binding sites. The binding ol plasminogen and/ or urokinase to these cells may lead to generation of cell- associated proteolytic activity which contributes to a variety of cellular functions.

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Antithrombin Activity of Intact Human Platelets

Thrombosis and Haemostasis ◽

10.1055/s-0038-1651361 ◽

1975 ◽

Vol 34 (01) ◽

pp. 115-126 ◽

Cited By ~ 3

Author(s):

Kiyoake Watanabe ◽

Francis C Chao ◽

James L Tullis

Keyword(s):

Antithrombin Iii ◽

Human Platelets ◽

Significant Loss ◽

Red Cells ◽

Antithrombin Activity ◽

Α2 Macroglobulin ◽

Rapid Reaction ◽

Pre Treatment ◽

Different Characteristics

SummaryAntithrombin activity has been identified in intact washed human platelets. An apparent activity was demonstrated at platelet concentrations above 0.31 × 109/ml, when platelet suspensions were incubated with 2.0 NIH units/ml of thrombin. Neither red cells nor white cells revealed antithrombin activity. No significant loss of the platelet antithrombin activity was observed after ten successive washings or after treatment of platelets with antibodies to antithrombin III or α2-macroglobulin. Almost the same amount of antithrombin activity as normal platelets was demonstrated in the platelets from an afibrinogenemic patient. Pre-treatment of platelets with trypsin, papain, and neuroaminidase reduced the activity significantly, whereas lipase was without effect. The platelet antithrombin reacted with thrombin in less than 3 seconds, and this rapid reaction of platelet antithrombin was different from that of plasma antithrombin III or fibrinogen. The thrombin-like clotting activity of ancrod was inhibited by fibrinogen but not platelets. Also, unlike plasma antithrombin III or fibrinogen, brief exposure to heat (56° C or 60° C) reduced considerable amounts of platelet antithrombin activity. These results suggest that platelets possess a specific antithrombin with different characteristics from other known antithrombins.

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In Vitro Assay of Platelet Adhesiveness with Washed and Tanned Human Red Cells

Thrombosis and Haemostasis ◽

10.1055/s-0038-1651281 ◽

1968 ◽

Vol 20 (03/04) ◽

pp. 384-396 ◽

Cited By ~ 1

Author(s):

G Zbinden ◽

S Tomlin

Keyword(s):

Platelet Adhesion ◽

Sodium Citrate ◽

Blood Platelets ◽

In Vitro Assay ◽

Red Cells ◽

Platelet Adhesiveness ◽

Vitro Assay ◽

In Vitro System ◽

Human Red Cells

SummaryAn in vitro system is described in which adhesion of blood platelets to washed and tannic acid-treated red cells was assayed quantitatively by microscopic observation. ADP, epinephrine and TAME produced a reversible increase in platelet adhesiveness which was antagonized by AMP. With Evans blue, polyanetholsulfonate, phthalanilide NSC 38280, thrombin and heparin at concentrations above 1-4 u/ml the increase was irreversible. The ADP-induced increase in adhesiveness was inhibited by sodium citrate, EDTA, AMP, ATP and N-ethylmaleimide. EDTA, AMP and the SH-blocker N-ethylmaleimide also reduced spontaneous platelet adhesion to red cells. No significant effects were observed with adenosine, phenprocoumon, 5-HT, phthalanilide NSC 57155, various estrogens, progestogens and fatty acids, acetylsalicylic acid and similarly acting agents, hydroxylamine, glucose and KCN. The method may be useful for the screening of thrombogenic and antithrombotic properties of drugs.

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Evaluation of a New Preparation of Urokinase

Thrombosis and Haemostasis ◽

10.1055/s-0038-1649107 ◽

1973 ◽

Vol 30 (01) ◽

pp. 114-122

Author(s):

C.R.M Prentice ◽

K.M Rogers ◽

G.P McNicol

Keyword(s):

Body Weight ◽

Maintenance Therapy ◽

Initial Dose ◽

Fibrinolytic Activity ◽

Pharmacological Effect ◽

Whole Body ◽

Fibrinolytic Agent ◽

Thromboplastic Activity

SummaryThe pharmacological effect of a new preparation of urokinase (Leo) has been studied, both in vitro and in six patients suffering from thrombo-embolic disorders. It was a non-toxic, effective fibrinolytic agent if given in sufficient dosage. A regimen consisting of an initial dose of 7,200 ploug units per kg body weight, followed by hourly maintenance therapy with 3,600 ploug units per kg intravenously, gave satisfactory evidence of whole body fibrinolytic activity. The preparation had minor but insignificant thromboplastic activity both when assayed in the laboratory and when given to patients.

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The Fractionation Properties of Human Factor VIII (Antihaemophilic Factor)

Thrombosis and Haemostasis ◽

10.1055/s-0038-1654503 ◽

1960 ◽

Vol 04 (02) ◽

pp. 253-260 ◽

Cited By ~ 1

Author(s):

Franco Gobbi

Keyword(s):

Factor Viii ◽

Human Factor ◽

Maximum Yield ◽

Factor Vii ◽

Precipitation Method ◽

Salting Out ◽

Human Factor Viii ◽

Plasma Factor ◽

Two Factors ◽

Thromboplastic Activity

SummaryThe fractionation properties of human Factor VIII (antihaemophilic factor, AHF, antihaemophilic globulin) have been studied using a plasma of congenital afibrinogenaemia as a starting material.From a fibrinogen-free plasma, Factor VIII does not precipitate with ethanol at a final concentration of 8%; on the contrary the maximum yield is reached at an ethanol concentration of 25%.With a precipitation method carried out by a one to ten dilution of plasma with distilled water and acidification by N/10 hydrochloric acid to a pFI 5.2, Factor VIII does not precipitate with the euglobulin fraction; when normal plasma is used, such a precipitation is almost complete.With the salting-out fractionation method by ammonium sulphate, Factor VIII precipitates at a concentration between 25 and 33% of saturation either from fibrinogen-free and from normal human plasma.A non-specific thromboplastic activity appears in the fractions prepared by every method. This activity, which is probably due to the activation of seric accelerators, is easily removed by Al(OH)s adsorption. Thus, in order to insure the specificity of Factor VIII assays, the preliminary adsorption of the fractions is indispensable before testing their antihaemophilic activity.Fibrinogen and Factor VIII have different and definite precipitation patterns. When these two factors are associated the fractionation properties of AHF appear quite modified, showing a close similarity to those of fibrinogen. This fact can explain the technical difficulties encountered in the attempt to purify the antihaemophilic factor, and the lack of reproducible procedures for removing fibrinogen without affecting Factor VII.

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