Platelet endothelial cell adhesion molecule (PECAM-1), a member of the Ig superfamily, is found on endothelial cells and neutrophils and has been shown to be involved in the migration of leukocytes across the endothelium. Adhesion is mediated, at least in part, through binding interactions involving its first N-terminal Ig-like domain, but it is still unclear which sequences in this domain are required for in vivo function. Therefore, to identify functionally important regions of the first Ig-like domain of PECAM-1 that are required for the participation of PECAM-1 in in vivo neutrophil recruitment, a panel of mAbs against this region of PECAM-1 was generated and characterized in in vitro adhesion assays and in an in vivo model of cutaneous inflammation. It was observed that mAbs that disrupted PECAM-1-dependent homophilic adhesion in an L cell aggregation assay also blocked TNF-α-induced intradermal accumulation of neutrophils in a transmigration model using human skin transplanted onto SCID mice. Localization of the epitopes of these Abs indicated that these function-blocking Abs mapped to specific regions on either face of domain 1. This suggests that these regions of the first Ig-like domain may contain or be close to binding sites involved in PECAM-1-dependent homophilic adhesion, and thus may represent potential targets for the development of antiinflammatory reagents.

Background and purpose: Recombinant human erythropoietin (rhEPO; Epoetin-a; PROCRITt) has been shown to exert neuroprotective and restorative effects in a variety of CNS injury models. However, limited information is available regarding the dose levels required for these beneficial effects or the neuronal responses that may underlie them. Here we have investigated the dose-response to rhEPO and compared the effects of rhEPO with those of carbamylated rhEPO (CEPO) in a model of cerebral stroke in rats. Experimental approach: Rats subjected to embolic middle cerebral artery occlusion (MCAo) were treated with rhEPO or CEPO, starting at 6 h and repeated at 24 and 48 h, after MCAo. Cerebral infarct volumes were assessed at 28 days and neurological impairment at 7, 14, 21 and 28 days, post-MCAo. Key results: rhEPO at dose levels of 500, 1150 or 5000 IU kg À1 or CEPO at a dose level of 50 mg kg À1 significantly reduced cortical infarct volume and reduced neurologic impairment. All doses of rhEPO, but not CEPO, produced a transient increase in haematocrit, while rhEPO and CEPO substantially reduced the number of apoptotic cells and activated microglia in the ischemic boundary region. Conclusions and implications: These data indicate that rhEPO and CEPO have anti-inflammatory and anti-apoptotic effects, even with administration at 6 h following embolic MCAo in rats. Taken together, these actions of rhEPO and CEPO are likely to contribute to their reduction of neurologic impairment following cerebral ischemia.

Endotoxic shock follows a cascade of events initiated by release of lipopolysaccharide during infection with Gram-negative organisms. Two overlapping 15-mer peptides were identified, corresponding to residues 91-108 of human lipopolysaccharide binding protein that specifically bound the lipid A moiety of lipopolysaccharide with high affinity. The peptides inhibited binding of lipopolysaccharide to lipopolysaccharide binding protein, inhibited the chromogenic Limulus amebocyte lysate reaction, and blocked release of tumor necrosis factor alpha following lipopolysaccharide challenge both in vitro and in vivo. These results suggest lipopolysaccharide binding protein residues 91-108 form at least part of the lipopolysaccharide binding site. Moreover, derivatives of lipopolysaccharide binding protein residues 91-108 might modulate lipopolysaccharide toxicity in the clinical setting.

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ether, affording 504 mg of crude material containing some unreacted starting material. The desired thioether 16 was isolated by column chromatography on silica gel using 30% ether-benzene.To a solution of 367 mg (1.07 mmol) of chromatographed thioether 16 in 5 ml of methylene chloride at 0°was added a solution of 190 mg (1.10 mmoles) of m-chloroperoxybenzoic acid in 5 ml of methylene chloride dropwise over 2.0 min. The solution was stirred for 2.0 hr at 0°and the solvent was removed by distillation at reduced pressure. The residue was taken up in ether and washed with two portions of saturated sodium bicarbonate solution to give the crude sulfoxide 17 as a white foam (276 mg).This material was directly converted to the methylene lactone 10 according to the procedure of Trost and Salzmann.14 A solution of 276 mg (0.77 mmol) of crude sulfoxide 17 in 8.0 ml of toluene was heated at reflux for 4.0 hr. The solution was cooled, diluted with ether, and washed with two portions of saturated sodium bicarbonate solution to afford 175 mg (98%) of crude product. Preparative thin layer chromatography on silica gel using 5% etherbenzene gave 4-deoxydamsin (Rf 0.39) as a white, crystalline solid:

Differentiation of lymphoid precursor cells in a variety of species is induced by polypeptide hormones such as thymopoietin for T cells and bursin for B cells. In the present experiments, bursin isolated from the bursa of Fabricius of chicken was found to induce the phenotypic differentiation of mammalian and avian B precursor cells but not of T precursor cells in vitro. Similarly, bursin increased cyclic guanosine monophosphate in cells of the human B-cell line Daudi but not in cells of the human T-cell line CEM. These inducing properties of bursin are the reverse of the inducing properties of thymopoietin produced by the thymus and are appropriate to a physiological B-cell-inducing hormone. A tripeptide sequence (lysyl-histidyl-glycyl-amide) was determined for bursin and confirmed by synthesizing this proposed structure and demonstrating chemical identity of the natural and synthetic peptides. Similarity of biological action was indicated in induction assays by elevation of cyclic adenosine monophosphate and guanosine monophosphate in Daudi B cells but not in CEM T cells.

Based on controlled studies, previous results suggesting that EPREX contains micelle-associated erythropoietin were incorrect. As with other surfactants and proteins, polysorbate 80 associates with erythropoietin in a defined stoichiometric ratio.