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PubMed1975

[Pathophysiological significance of endotoxins].

The biological activities of endotoxin are manifold. Besides the drop in platelets and the biphasic change in the number of leukocytes, severe disturbances in the capillary bed are among the first changes observed following the administration of endotoxin. It is well known that endotoxins cause the release of various vasoactive mediators. According to our results endotoxins enhance the activity of histamine and serotonin; these findings may contribute to a better understanding of the action of histamine and serotonin in the early post-endotoxin phase. The histamine-sensitizing effect of endotoxins is not prevented by antihistamines. Endotoxins and biogenic amines cause similar disturbances in the capillary bed. The changes that are observed in the content of the vessels, the vessel wall, and the perivascular region are the following: slowing down of the blood stream, degranulation of perivascular mast cells, granulocytosis, wall adhering granulocytes, plasma skimming, rouleaux-formation of erythrocytes, reduction in plasticity of many erythrocytes, acanthocytes, acanthocytosis, appearance of spherocytes and microcytes, and formation of massive aggregates of platelets and of microthrombi. Also, occasionally cell aggregates dissolve and as microemboli form new thrombi. Swelling of pericytes, endothelial, and periendothelial cells is observed, and dissociation and deformation of the endothelial cells occur. By means of contact of the vessel contents with the collagen, there is an additional activation of the coagulation system by factor XII possible. The changes of the epithelial lining and the wall adhering cells enhance the narrowing of the vessel lumen. Prestasis and occasionally stasis occur. One observes increased swelling of the endothelial and periendothelial cells, increased permeability of the vessel wall, passage of plasma and occasionally blood cells, especially erythrocytes, through the endothelium and massive microbleedings. While stasis is observed in the nutritive capillaries, in regions where arteriolar-venular shunts exist the flow continues. The systemic blood pressure may therefore remain unchanged during this phase, although the severe disturbances described occur in the capillary bed. Metabolic alterations, especially in the carbohydrate metabolism are mentioned.

Animals↗
PubMed1984

[Thrombogenicity of a new prothrombin complex concentrate].

A prothrombin complex concentrate produced according to a new procedure was tested for potential thrombogenicity in vitro and in vivo. The results obtained by in vitro methods (NAPTT, TGt50, determination of the hydrolytic index) were not in the critical range of thrombogenicity. An effective dose of 175 U/kg for thrombus formation assessed in the stasis model of Wessler suggested comparatively low thrombogenicity. In the non stasis model no changes in the haemostaseological variables indicative of consumption reaction were observed after infusion of 125 U/kg for 30 min in rabbits. In the organs investigated (heart, liver, kidneys, adrenals) no thrombin were detected morphologically.

Animals↗
PubMed1984

The contact phase of blood coagulation in diabetes mellitus and in patients with vasculopathy.

The contact phase has been studied in diabetics and patients with macroangiopathy. Factor XII and high molecular weight kininogen (HMWK) are normal. C1-inhibitor and also alpha 2-macroglobulin are significantly elevated in diabetics with complications, for alpha 2-macroglobulin especially in patients with nephropathy, 137.5% +/- 36.0 (p less than 0.001). C1-inhibitor is also increased in vasculopathy without diabetes 113.2 +/- 22.1 (p less than 0.01). Prekallikrein (PK) is increased in all patients' groups (Table 2) as compared to normals. PK is particularly high (134% +/- 32) in 5 diabetics without macroangiopathy but with sensomotor neuropathy. This difference is remarkable because of the older age of diabetics and the negative correlation of PK with age in normals.

Blood Coagulation↗
PubMed1981

Studies on a circulating anticoagulant in procainamide-induced lupus erythematosus.

Circulating anticoagulant activity that had at least two distinct mechanisms--one directed against factor XII and one directed against blood thromboplastin (prothrombin activator complex)--developed in a patient with clinical and laboratory evidence of procainamide hydrochloride-induced systemic lupus erythematosus. The anticoagulant activity behaved as a gamma-globulin in chromatographic and electrophoretic analyses, with the majority of activity behaving as an IgM immunoglobulin. Despite markedly abnormal coagulation study results, no clinical bleeding occurred. Anticoagulant activity paralleled clinical and laboratory evidence of the inflammatory disease and improved on discontinuance of procainamide therapy.

Aged↗
PubMed1983

Inhibitory effect of aprotinin and gabexate mesilate on human plasma kallikrein.

Prekallikrein (PK) in human plasma was activated with kaolin in the presence of protease inhibitors aprotinin (Trasylol) and gabexate mesilate to investigate a difference in the inhibitory activity of plasma kallikrein (K) between these inhibitors. Benzoyl-prolyl-phenylalanyl arginine-p-nitroanilide (PPAN) cleavage of purified plasma K was markedly inhibited by aprotinin and gabexate mesilate, and acetyl-glycyl-l-lysine methyl ester hydrolysis of purified PK activator was slightly inhibited. PPAN cleavage of plasma K-alpha2 macroglobulin complex was hardly inhibited by aprotinin while PPAN cleavage of the complex was markedly inhibited by gabexate mesilate. The inhibitory activity of gabexate mesilate towards plasma K completely disappeared after 10 min incubation with plasma at 37 degrees C and also in 30 min on the experiment in which the time course of kaolin-induced PK activation was observed at 10 degrees C. On the other hand, the inhibitory activity of aprotinin towards plasma K never changed after 10 min incubation with plasma at 37 degrees C or 30 min incubation with plasma at 10 degrees C. From the results it is concluded that a predominant effect of aprotinin in human plasma is due to its stability in contrast to instability of gabexate mesilate.

Adult↗
PubMed1984

Regulation of the coagulant activity and surface binding of high molecular weight kininogen.

Cleavage of the procofactor, high molecular weight kininogen, by kallikrein, is required for expression of it cofactor activity. Coagulant activity associated with the light chain of high molecular weight kininogen is destroyed by proteolysis by factor XIa. The heavy chain of high molecular weight kininogen augments the binding of the light chain to activating surfaces without itself expressing coagulant activity.

Blood Coagulation Factors↗
PubMed1983

Wasp sting anaphylaxis.

Profuse hemostatic defects were demonstrable 14 hr after wasp sting anaphylaxis. The patient's plasma contained an agent or agents that interfered with the action of thrombin, impeding the release of fibrinopeptide A from fibrinogen and the hydrolysis of the synthetic amide H-D-prolyl-L-phenylalanyl-L-arginine p-nitroanilide. This inhibitor could not be equated with known plasma inhibitors of thrombin nor with heparin. Additionally, the titers of nearly all other known clotting factors were reduced as compared to levels obtained after the patient's recovery. Of particular interest were profound reductions in the titers of proaccelerin (factor V) and high molecular weight kininogen. A normal titer of Hageman factor (factor XII) argued against participation of contact-activated mechanisms in the induction of the multiple abnormalities observed. Attempts to demonstrate the release of procoagulant or anticoagulant substances from the patient's convalescent blood, plasma, serum, or leukocytes upon challenge with wasp venom were unsuccessful. The observations reported confirm and extend information concerning hemostatic abnormalities in anaphylaxis, and point out the need to examine further this puzzling association.

Adult↗
PubMed1984

Activation of coagulation factors on the surface of platelets.

Platelet physiology and coagulation biochemistry have traditionally been studied and conceptualized as separate and distinct entities. This brief summary of platelet-coagulant protein interactions presents an alternative viewpoint which emphasizes the effects of platelets in coagulation and the effects of coagulation proteins on platelet physiology. These interrelationships are so intimate and important that any consideration of the hemostasis mechanism that fails to take them into account is meaningless.

Blood Coagulation↗
PubMed1984

[Fibronectin--its functions and roles in tissue repair].

Fibronectin is a recently characterized 4.4 X 10(5) dalton glycoprotein consisting of two probably identical 2.2 X 10(5) dalton subunits held together by disulfide linkages. It is present as a soluble fraction in plasma at about 30mg/dl and is widely distributed as an insoluble component to various tissues, in close association with fibrillar structures of connective tissue matrices, basement membranes and certain mesenchymal cells including fibroblasts and smooth muscle cells. Fibronectin binds to fibrin and collagen reversibly and crosslinks to these filamentous proteins catalyzed by the activated blood coagulation factor XII (plasma transglutaminase). Plasma fibronectin appears to be utilized at the healing wounds, thus its concentration decreases during early postoperative days. Immunofluorescence study shows that fibronectin is closely associated with newly generated fibroblasts and fibrillar structures in the early stage of wound healing, and that it diminishes in accordance with the maturation of collagen fibers. Plasma fibronectin is shown to function to remove the colloidal debris from blood via the reticuloendothelial system and to play important roles in organizing the cytoskeleton and in the migration and spreading of interstitial cells. Thus fibronectin seems to play a pivotal role in the tissue repair via a variety of biological functions.

Female↗