We have investigated the effect of simulated saturation diving on the activation of intrinsic and extrinsic coagulation pathways. Thirty-one male divers divided into two groups were tested in ...decompression habitat LSH-200. The first group of 16 divers was subjected to hyperbaric exposure at pressure of 180 kPa with air as a breathing mixture, and the second group of 15 divers, exposed to a pressure of 400 kPa with a heliox breathing mixture (helium-oxygen mixture: pO2, 40 kPa; pN2, 40 kPa; pHe, 420 kPa). The concentrations of tissue factor, tissue factor pathway inhibitor, factors XII, X, VII, and I, prothrombin fragment F1 + 2, and thrombin-antithrombin complex as well as platelet count, prothrombin time, activated partial thromboplastin time, plasmin-antiplasmin complex (PAP) and D-dimers were measured. We did not detect activation of the extrinsic coagulation pathway after decompression. There was a statistically significant decrease in platelet counts and factor I, XII and X concentrations after air-diving, and a potent and statistically significant increase of PAP concentration in both groups of divers. We suggest that saturated air or heliox diving followed by decompression have little if any effect on thrombin generation. Saturated air diving, however, may induce a decrease in platelet count and factor XII concentration. The observed elevation of PAP concentrations in both groups of divers suggests possible activation of fibrinolysis. The exact effect of diving and decompression on fibrinolytic system has to be further investigated.
In this study we compared the antithrombotic and anticoagulant properties of sodium and calcium derivatives of pentosan polysulfate (Na-PPS, Ca-PPS), unfractionated heparin (UFH), and ...low-molecular-weight heparin (Fraxiparin). The antithrombotic effects of these agents have been investigated in an experimental thrombosis model in which rat mesenteric venules with a diameter of 20-30 microm were injured by well-defined argon laser lesions. Furthermore, the in vivo and in vitro anticoagulant activities activated partial thromboplastin time (aPTT), Heptest of these agents have been studied. Thrombus formation was significantly inhibited after s.c. injection of Na-PPS and Ca-PPS in doses >10 mg/kg. The duration of the antithrombotic effect lasted 8 h for Na-PPS and 12 h for Ca-PPS. After oral administration of Na-PPS, an antithrombotic effect was not observed. Oral application of Ca-PPS in doses >20 mg/kg significantly inhibited thrombus formation. Na-PPS and Ca-PPS markedly prolonged clotting time in aPTT and Heptest in concentrations ranging from 0.01 to 0.2 mg/ml rat PTT. Two h after s.c. administration of these agents in a dose of 10 mg/kg, the aPTT increased threefold and the Heptest 2.5-fold compared with controls. After oral application of 50 mg/kg Na-PPS and Ca-PPS, no effect on the coagulation test could be measured. Intravenous injection of UFH prolonged the Heptest after 1 min and the aPTT after 30 min. In ex vivo studies of aPTT and Heptest performed in rat plasma between 2 and 24 h after s.c. injection of 0.2 mg/kg Fraxiparin, no inhibition of any coagulation test was measured. The antithrombotic effect of 0.2 mg/kg Fraxiparin after s.c. injection was significant. Intravenous injection of 20 U/kg UFH significantly inhibited thrombus formation. The smallest antithrombotic effect was after i.v. injection of UFH.
In the present study we have compared the antithrombotic and anticoagulant properties of sodium and calcium derivatives of pentosan polysulphate (Na-PPS, Ca-PPS). The antithrombotic effect of these ...agents have been investigated in an experimental thrombosis model in which rat mesenteric venules diameter of 20-30 microm were injured by well defined Argon laser lesions. Furthermore, the in vivo and in vitro anticoagulant activities (aPTT, Heptest) of these agents have been studied. Thrombus formation was significantly inhibited after s.c. injection of Na-PPS and Ca-PPS in doses above 10 mg/kg. The duration of the antithrombotic effect lasted 8 h for Na-PPS and 12 h for Ca-PPS. After oral administration of Na-PPS an antithrombotic effect was not observed. Oral application of Ca-PPS in doses higher than 20 mg/kg significantly inhibited thrombus formation. Na-PPS and Ca-PPS markedly prolonged clotting time in aPTT and Heptest in concentrations ranging from 0.01 to 0.2 mg/ml rat PTT. Two h after s.c. administration of these agents in a dose 10 mg/kg, the aPTT increased 3-fold and Heptest 2.5-fold compared to controls. After oral application of 50 mg/kg Na-PPS and Ca-PPS no effect on coagulation test could be measured.
Platelet-induced thrombin generation time (PITT) is a newly developed global coagulation assay in which a small amount of partially anticoagulated platelet-rich plasma (PRP) is rotated in a ...disc-shaped cuvette within the light beam of a photometer. The time intervals from onset of rotation until aggregation and coagulation of the sample are registered. The aim of our study was to compare platelet activation with generation of thrombin during rotation of PRP in PITT system. Aliquots of PRP were taken before, 1, 3, and 8 min after the onset of rotation as well as at the beginning of aggregation and shortly before coagulation. Thrombin activity was measured with chromogenic substrate S-2238. We have also measured the level of generated prothrombin activation fragment 1+2 (F1+2), which reflects the concentration of liberated thrombin. Platelet activation was assayed by means of platelet factor 4 (PF4) and β-thromboglobulin (β-TG) concentration and registration of the aggregation. The concentrations of the F1+2, PF4, β-TG increased very slowly from the beginning of the test until aggregation occurred. From the start of aggregation, the levels of F1+2 rose rapidly. In contrast to the F1+2 measurements, thrombin activity has not been detected from onset of rotation until the end of the test. Only trace thrombin activity was detectable just after the plasma sample had been clotted in the cuvette. Our results demonstrate that there exists a close relationship between platelet activation and thrombin generation. Viable platelets, which adhered to the cuvette walls, form an active template on which thrombin can be generated from prothrombin.
Monocytes are highly versatile cells, and their functional capabilities include roles as mediators of inflammation and of the immune response. Moreover, monocytes are involved in vascular lesions, ...due to their interaction with the endothelium and platelets, and they have been imputed to play a relevant role in the pathogenesis of atherosclerosis. The article describes the potential regulatory role of these cells and interaction with platelets in this process.
Monocytes may contribute to a coagulation process by expression of the tissue factor and by synthesizing factors V, VII, X and XIII. Cultured blood monocytes also express both the tissue plasminogen ...activator and the plasminogen activator inhibitor I. The present study assesses the ability of human monocytes to secrete protein C and its cofactor protein S, which are potent inhibitors of the clotting cascade. Monocytes derived from the blood of healthy volunteers and prepared according to Boyum were cultured for up to 36 hours with or without lipopolisaccharide from Escherichia coli. After different times of incubation, the concentrations of proteins C and S in the supernatants were measured in order to determine synthesis of proteins, monocytes were cultured in the presence or absence of cycloheximide, the protein synthesis inhibitor. The concentration of protein C was estimated by means of the ELISA Protein C test (Boehringer Mannheim). Protein S concentrations were measured by rocket immunoelectrophoresis according to Laurell, using monospecific antisera (American Diagnostica Inc., N.Y.). The study showed that human monocytes, when stimulated by lipopolisaccharide, release proteins C and S in vitro. The concentration of these proteins in the culture supernatants markedly increased with time during the 36-hour observation. The supernatants obtained from the culture of unstimulated monocytes did not contain detectable quantities of the investigated proteins. The exposure of the cells to cycloheximide did not suppress the release of proteins C and S. In conclusion, our results suggest that monocytes are not able to synthesize proteins C and S. They can only release these factors. Furthermore, monocytes may be responsible for coagulation due to the inactivation of factors Va and VIIIa by protein C.
The ability of human peripheral blood monocytes to secrete plasma serine protease inhibitors was studied. Monocytes from blood obtained from healthy young adult volunteers were cultured for up to 36 ...h with and without lipopolysaccharide from Escherichia coli. The concentrations of plasma serine protease inhibitors in monocyte culture supernatants were measured by using rocket immunoelectrophoresis. The study showed that human monocytes stimulated with lipopolysaccharide in vitro release antithrombin III, C1 esterase inhibitor, alpha 2-antiplasmin, and alpha 2-macroglobulin.
The effect of increased respiratory resistance (stenosis of the trachea) on glycogen and triglyceride levels in the diaphragm (D) and intercostal (external-IE, internal-II) muscles was studied in the ...rat. Tracheal stenosis resulted in a reduction of glycogen level in the muscles. For the fed rats the reductions were: D-45 and 79%, IE-14 and 30%, II-14 and 35%, 0.5 and 3 h after stenosis, respectively. For rats fasted for 24 h the reductions were: D-64 and 86%, IE-33 and 71%, II-40 and 82%, after 0.5 and 3 h respectively. The level of triglycerides in the muscles was stable during stenosis in the fed group, whereas in the fasted group it were reduced in the diaphragm by 50% after 0.5 h, and by 52% after 3 h. It is concluded that both endogenous and blood-born energy fuels are utilized by the respiratory muscles during increased resistance breathing.
Prostaglandins have been proposed as intercellular humoral mediators in the immune response and characterised as regulatory agents in the control of intracellular metabolism. The aim of this work was ...to determine PGE and PGF2 alpha concentrations in the blood plasma and in the supernatant of 96 hour PHA stimulated and unstimulated leukaemic cell cultures of CLL patients. 62 patients with CLL classified in the 1st or 4th stage according to RAI and 23 healthy individuals were investigated. The proliferation degree of the culture cells was tested by incorporating tritiated thymidine. The prostaglandin concentrations was estimated by the isotopic method using RIA-kit. In the 4th stage of CLL a low value of blastogenic transformation was observed, whereas in the 1st stage the value were similar to those of the control group. It was shown that in the 4th stage of the disease an increase in the PGE concentrations occurs in the blood plasma and the culture supernatant without PHA together with a significant decrease in the PGF2 alpha in the culture supernatant, whereas in the 1st stage a significant decrease in the PGE in the culture supernatant with PHA as compared with those of the control group is noted. These results may indicate on antagonistic action of PGE and PGF2 alpha in leukaemic cell proliferation.
