The effects of hydroxyethyl starch (HES) on hemostasis were investigated extensively. In order to simulate acute blood loss due to surgery or trauma, one unit (450 ml) of blood was drawn from normal healthy men. This was followed by a 1-liter infusion over 60 minutes of either 6 percent HES, 5 percent albumin, or 0.9 percent sodium chloride (NaCl) as replacement. Coagulation studies were performed before phlebotomy, before infusion and at 0, 4, 20, 27, and 92 hours following infusion. Following infusion of HES and albumin, plasma fibrinogen and antithrombin-III levels fell slightly due to plasma volume expansion and hemodilution. In subjects receiving HES, partial thromboplastin times (PTTs) were significantly (p less than .05) prolonged and factor VIII activities were significantly (p less than .05) decreased when compared to the albumin and NaCl groups. These findings could not be attributed solely to hemodilution. The effects of HES on PTT and factor VIII could not be correlated with plasma HES levels; neither could they be reproduced in vitro by mixing HES with normal plasma. Mean values of the following studies remained normal after infusion of all replacement fluids: prothrombin time, bleeding time, fibrin monomer, fibrin-fibrinogen degradation products, platelet adhesion, circulating platelet aggregates, and platelet count.(ABSTRACT TRUNCATED AT 250 WORDS)

Human intelectin-1 (hITLN-1) is a 120-kDa lectin recognizing galactofuranosyl residues found in cell walls of various microorganisms but not in mammalian tissues. Although mouse intelectin-1 (mITLN-1) has been identified previously, its biochemical properties and functional characteristics have not been studied. Therefore, we have compared structures and saccharide-binding specificities of hITLN-1 and mITLN-1 using recombinant proteins produced by mammalian cells. Recombinant hITLN-1 is a trimer, disulfide-linked through Cys-31 and Cys-48, and Nglycosylated at Asn-163. Despite 84.9% amino acid identity to hITLN-1, recombinant and intestinal mITLN-1 are unglycosylated 30-kDa monomers. Recombinant hITLN-1, as well as recombinant and intestinal mITLN-1 were purified by Ca 2+ -dependent adsorption to galactose-Sepharose. In competitive binding studies, hITLN-1 was eluted from galactose-Sepharose by 100 mM 2-deoxygalactose, a galactofuranosyl disaccharide, D-xylose, and both D-and L-ribose. In contrast, mITLN-1 was partially eluted by the galactofuranosyl disaccharide, and only minimally by the other saccharides indicating that the two intelectins have different saccharide-binding specificities. When the N-and Cterminal regions of hITLN-1 were replaced, respectively, with those of mITLN-1, galactose-Sepharose binding was associated with the C-terminal regions. Finally, hITLN-1 binding to galactose-Sepharose was not affected by the substitution of the Cys residues in the N-terminal region that are necessary for oligomer formation, nor was it affected by the removal of the N-linked oligosaccharide at Asn-163. Although both hITLN-1 and mITLN-1 recognize galactofuranosyl residues, our comparative studies, taken together, demonstrate that these intelectins have different quaternary structures and saccharide-binding specificities.

Hetastarch, the currently marketed preparation of hydroxyethyl starch, affects coagulation by prolonging partial thromboplastin, prothrombin, and bleeding times; by lowering clotting proteins such as fibrinogen via hemodilution; by lowering clotting factor VIII (coagulant, von Willebrand antigen, and von Willebrand activity) to a greater degree than can be explained simply by hemodilution (i.e., presumably factor VIII affected by both hemodilutional plus additional, independent effects); and, finally, by shortening thrombin, reptilase, and urokinase-activated clot lysis times. Pentastarch, a new analog of hetastarch, was found to exert lesser effects on blood coagulation, despite its greater hemodiluting properties. When compared with hetastarch, pentastarch had little effect on factor VIII (except that due to hemodilution), shortened thrombin times to a significantly lesser degree, exerted no effect on the urokinase-activated clot lysis time, and did not prolong the bleeding time. Even when plasma hydroxyethyl starch levels were similar, pentastarch seemed to alter the results of coagulation assays to lesser degree than did hetastarch, which suggests the possibility of greater safety. Therefore, pentastarch may be a desirable drug, not only for leukapheresis, but also for plasma volume expansion in trauma and surgical patients who often have additional hemostatic abnormalities that place them at increased risk of hemorrhage.

Hosts infected with low doses of mycobacteria develop T helper cell type 1 (Th1) immunity, but at relatively higher doses, a switch to Th2 immunity occurs. Prostaglandin E2 (PGE2) is a proposed mediator of the Th1-to-Th2 shift of immune responses, and mycobacterial products induce PGE2-releasing macrophages (PGE2-MØ) in the mouse spleen in a dose-dependent manner. Splenic PGE2-M Ø from Balb/c mice, given 0.01 or 1 mg heat-killed (HK) Mycobacterium bovis bacillus Calmette-Guerin (BCG) intraperitoneally (i.p.), were characterized by the ex vivo release of PGE2 (>10 ng/10(6) cells), cytokine production, and expression of PGG/H synthase (PGHS)-1, PGHS-2, cytosolic PGE synthase (PGES), and microsomal PGES-1. At Day 14 after the treatment, mice treated with 1 mg, but not 0.01 mg, BCG had increased levels of PGHS-2+ PGE2-MØ, total serum immunoglobulin E (IgE), and serum IgG1 antibodies (Th2 responses) against heat shock protein 65 and purified protein derivative. Cultures of spleen cells isolated from these mice expressed interleukin (IL)-4 and IL-10 in recall responses. Treatment of mice receiving 1 mg BCG with NS-398 (a PGHS-2 inhibitor, 10 mg/kg i.p., daily) resulted in enhanced interferon-gamma (IFN-gamma) production with reduced IL-4 and IL-10 production in recall responses. This treatment also resulted in decreased total serum IgE levels. Treatment of C57Bl/6 mice with HK-BCG (0.5 mg dose) also induced a mixture of Th1 and Th2 responses, although IFN-gamma production was markedly increased, and IL-4 was decreased compared with Balb/c mice. Thus, our results indicate that by 14 days following treatment of mice with high doses of HK-BCG, splenic PGE2-MØ formation is associated with a PGHS-2-dependent shift from Th1-to-Th2 immune responses.

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