To investigate the coagulant and fibrinolytic potential of peritoneal macrophages, after short-term exposure to dialysis solutions intraperitoneal (IP) injection of these hyperosmolar glucose solutions was performed in rats. During the 72-hour postinjection period, the dialysis solutions and, as controls, Ringer's lactate and Ringer's lactate-glucose all induced a similar increase in the number of polymorphonuclear cells and macrophages within a maximum of 24 or 48 hours after their IP injection. These findings demonstrate that IP injection of any dialysis solution results in a moderate non-specific inflammatory cell harvesting. Compared with activity induced by the control solutions, no significant increase of procoagulant and fibrinolytic activities, identified respectively by the presence of thromboplastin and plasminogen activator, was observed in peritoneal macrophages obtained 48 hours after injection of the solution with the highest glucose concentration. However, the level of procoagulant activity could increase as a result of different manufacturers' processing of the solutions. That the basal level of macrophage functions may be modified suggests that this cell may initiate coagulolytic conditions in the peritoneal cavity, especially in the course of IP injection of dialysis solutions.

Polyurethanes (PUs) represent a heterogenous family of artificial P materials that can be synthesized ranging from soft rubbery materials to rigid rough polymers. They are described as &dquo;biomedical grade&dquo; if they are &dquo;systemic pharmacologically inert substances designed for implantation within living systems&dquo; [1]. The most common PUs used as biomaterials are polyetherurethanes (PEU) which consist of chains of aromatic or aliphatic &dquo;hard&dquo; segments connected by flexible polyether &dquo;soft&dquo; segments (Figure 1). The hard and soft segments of PUs separate into phases and the bulk material consists of domains of hard segments suspended in soft segment matrix, which give the PUs their unique combination of flexibility and strength. PUs exhibit several properties that make them particularly attractive for biomedical applications [2] (Table 1).

An in vitro method has been developed for human non-anticoagulated blood to evaluate the enhancing effect of hemostatic agents on both plasmatic and cellular activation of the coagulation cascade. The coagulation time and the sequential generation of fibrinopeptide A (FpA) have been used as parameters. The kinetics of generation of FpA has been modelized and mathematically analyzed using the latence time, the slope of the linear part of the curve, and the time necessary to reach half maximal amplitude of FpA in the tube. A maximal amplitude of FpA in the tube. A very precise evaluation of the hemostatic activity of five different molecules, four being collagenous in nature, is given.

Bulk heparinized catheters (1 mm internal diameter) containing 10 % heparin ionically bound, were tested in four human volunteers. Catheters containing 0 % and 10 % heparin were compared in each individual using ultrasound microflow velocimetry, permeability test, sequential determinations of activated partial thromboplastin time, heparin levels and generation of Fibrinopeptide A, ß thromboglobulin and Platelet factor 4. Although the release of heparin expressed by its anti-IIa activity is of similar range in the four individuals the release of anti-Xa activity is variable and generally of greater magnitude, suggesting a privileged migration of low molecular weight components of heparin. These antiproteasic activities of heparin are sufficient to inhibit fibrin formation and blood coagulation despite their relative inability to prevent platelet activation.