ISSN:1424-8832    

DOI:10.1159/000214082

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

Human platelets, prelabelled with [3H]-adenine in vitro, were aggregated biphasically by bovine fibrinogen/factor VIII, and the amounts and specific radioactivity of ADP and ATP as well as the radioactivity of ATP, ADP, AMP, IMP and hypoxanthine + inosine were determined intracellularly and extracellularly. During the second phase of aggregation, ATP and ADP were released (50 % of total) with a specific radioactivity 15–20 times lower than that of the ATP and ADP retained in the cells. The specific radioactivity of the ATP and ADP in the cells increased during release. Radioactive ATP was converted to radioactive hypoxanthine during release. These findings correlated well with those obtained with collagen, and indicate that bovine factor VIII induces the platelet release reaction whereby the storage (non-metabolic) pool of ATP and ADP is released while the metabolic pool is retaine

ISSN:1424-8832    

DOI:10.1159/000214083

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

The influence of intravenously administered acetylsalicylic acid (ASA) on the kinetics of platelet function was examined in 10 patients. Simultaneously, assays of salicylate in plasma were performed. A significant inhibition of platelet aggregation as well as PF 3 and PF 4 availabilities could be demonstrated 2 min after injection. A decrease of platelet adhesion was significant after 15 min. The inhibition of platelet functions was still present after 24 h and was partially demonstrable after 72 h. The concentration of salicylate in plasma 2 min after injection of ASA was only about two thirds of the level calculated from mere distribution in circulation. After 1 h, half of the initial salicylate had disappeared from plasma. No salicylate could be found after 24 hours. ASA also depressed platelet functions when added to platelet-rich plasma in vitro in a concentration of 100 μg/ml. Inhibition of platelet aggregation and of PF 4 availability were dependent on the time of incubation. Their onset was much slower in vitro than in vivo. No inhibition of the PF 3 availability could be found in vitro. The inhibition of platelet functions by ASA is demonstrable almost immediately after injection while the duration of this inhibition is considerably longer than the elimination time of salicylate from plasma. This allows the conclusion that a direct intravascular reaction between ASA and platelets occurs and that the inhibition of platelet functions is irreversible

ISSN:1424-8832    

DOI:10.1159/000214084

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

102 sera from polytransfused patients have been screened in platelet aggregometry. Anti-human platelet isoantibodies, tested against ‘responsive’ human platelets in PRP, give in the aggregometer a decrease in optical density recorded as a sigmoidal curve. In the first step of reaction PF3 availability suggests that the primary action of antibody is to damage the platelet membrane. The second step might be a true aggregation (an ADP-mediated platelet clumping) or a platelet lysis, depending on the type and the potency of antibody, on the type of platelets (normal or thrombasthenic) and on some experimental conditions. These conclusions, confirmed by electron microscopy findings, suggest that aggregometry is a very rapid and simple method of detecting platelet antibod

ISSN:1424-8832    

DOI:10.1159/000214085

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

Electroencephalography has been performed in a series of patients with haemophilia and Christmas disease because of the suggestion by other authors of a high incidence of abnormality. In an adult population of haemophiliacs no difference was found in the incidence of abnormalities compared with the general hospital population.

ISSN:1424-8832    

DOI:10.1159/000214086

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

The catabolism of rabbit fibrinogen labelled with radioactive iodine was studied over a period of 7–9 days in normal rabbits and in rabbits with indwelling intravenous catheters. The labelled fibrinogen was highly clottable and homogeneous on immunoelectrophoresis and disc electrophoresis. The protein-bound 125I-activity amounted to at least 99%. Normal rabbits with a weight between 1.6 and 2.2 kg exhibited a mean plasma volume of 41.65 ml/kg. A mean half-life time of 1.69 days and a mean fractional catabolic rate of 59.8% of the plasma fibrinogen pool per day was computed by tracing labelled fibrinogen. The absolute catabolic rate revealed a mean value of 58.7 mg/kg body weight/day. Comparable results were obtained for all three labelled fibrinogen batches. A siliconized polyvinyl tubing with an outer diameter of 2.0 mm inserted into a jugular vein up to a length of 10–12 cm and indwelling for more than 10 days did not significantly influence the parameters studied for controlling the fibrinogen catabolism except for the absolute catabolic rate of 112.8 mg/kg/day which differed significantly from that of the control group. Thus, the indwelling intravenous catheter had no or only a minor effect on the activation of intravascular coagulat

ISSN:1424-8832    

DOI:10.1159/000214087

出版商:S. Karger AG    

年代:1975

数据来源: Karger

摘要:

The fibrinogenolytic activity of the salivary gland extract from the Brazilian blood-sucking leech Haementeria lutzi Pinto 1920 is characterized. The substance, named here hementerin, is stable and active at very low protein concentration, does not exhibit direct proteolytic activity on casein, fibrinogen, or fibrin, and is able to activate the human plasma fibrinolytic system in the presence of a serum cofactor and/or calcium. This indirect activation mechanism distinguishes hementerin from hirudin and shows a similarity with streptokinase. The effect on blood coagulation tests is reported.

ISSN:1424-8832    

DOI:10.1159/000214088

出版商:S. Karger AG    

年代:1975

数据来源: Karger