Although it is well recognized that human platelet responses to ␣-thrombin are mediated by the protease-activated receptors PAR-1 and PAR-4, their role and relative importance in plateletdependent human disease has not yet been elucidated. Because the expression profile of PARs in platelets from nonprimates differs from humans, we used cynomolgus monkeys to evaluate the role of PAR-1 in thrombosis. Based on reverse transcription-polymerase chain reaction, PAR expression in platelets from cynomolgus monkeys consisted primarily of PAR-1 and PAR-4, thereby mirroring the profile of human platelets. We probed the role of PAR-1 in a primate model of vascular injury-induced thrombosis with the selective PAR-1 antagonist (␣S)

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.

Vascular access complications are a major problem in hemodialysis patients. Native arteriovenous fistulae, historically the preferred mode of access, have a patency rate of only 60% at 1 year. The most common mode of failure is due to progressive stenosis at the anastomotic site. We have previously demonstrated that perivascular endothelial cell implants inhibit intimal thickening following acute balloon injury in pigs and now seek to determine if these implants provide a similar benefit in the chronic and more complex injury model of arteriovenous anastomoses. Side-to-side femoral artery-femoral vein anastomoses were created in 24 domestic swine and the toxicological, biological and immunological responses to allogeneic endothelial cell implants were investigated 3 days and 1 and 2 months postoperatively. The anastomoses were wrapped with polymer matrices containing confluent porcine aortic endothelial cells (PAE; n = 14) or control matrices without cells (n = 10). PAE implants significantly reduced intimal hyperplasia at the anastomotic sites compared to controls by 68% (p <0.05) at 2 months. The beneficial effects of the PAE implants were not due to differences in the rates of reendothelialization between the groups. No significant immunological response to the allogeneic endothelial cells that impacted on efficacy was detected in any of the pigs. No apparent toxicity was observed in any of the animals treated with endothelial implants. These data suggest that perivascular endothelial cell implants are safe and reduce early intimal hyperplasia in a porcine model of arteriovenous anastomoses.

Blood oxygen level dependent (BOLD) imaging in awake mice was used to identify differences in brain activity between wild-type, HETzQ175, and HOMzQ175 genotypes in response to the odor of almond. The study was designed to see how alterations in the huntingtin gene in a mouse model of Huntington’s disease would affect the perception and processing of almond odor, an evolutionarily conserved stimulus with high emotional and motivational valence. Moreover, the mice in this study were “odor naïve,” i.e., never having smelled almond or any nuts. Using a segmented, annotated MRI atlas of the mouse and computational analysis, 17 out of 116 brain regions were identified as responding differently to almond odor across genotypes. These regions included the glomerulus of the olfactory bulb, forebrain cortex, anterior cingulate, subiculum, and dentate gyrus of the hippocampus, and several areas of the hypothalamus. In many cases, these regions showed a gene-dose effect with HETzQ175 mice showing a reduction in brain activity from wild-type that is further reduced in HOMzQ175 mice. Conspicuously absent were any differences in brain activity in the caudate/putamen, thalamus, CA3, and CA1 of the hippocampus and much of the cortex. The glomerulus of the olfactory bulb in HOMzQ175 mice showed a reduced change in BOLD signal intensity in response to almond odor as compared to the other phenotypes suggesting a deficit in olfactory sensitivity.

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Bifunctional chelators for labeling antibodies with 99mTc based on the N3S core of (mercaptoacetyl)-triglycine having ester or amide linking moieties were synthesized and site-specifically attached to the sulfhydryl groups of the Fab' fragment of antimyosin. Protein labeling was quantitative after 15 min; postlabeling purification was not necessary. The radiolabeled conjugates exhibited no loss of immunoreactivity. Under basic conditions, the ester-linked conjugate lost 95% of the radiolabel in the form of the 99mTc complex of (mercaptoacetyl)triglycine as determined by RP-HPLC, while the radioactivity in the amide-linked conjugate remained completely bound to the protein. In a mouse biodistribution study, the ester-linked conjugate showed a 2-fold enhancement in clearance from the kidney when compared to the amide-linked product.

Abstract-A central role for leukocytes in neointimal hyperplasia after arterial injury is suspected. However, the relative importance of neutrophils and monocytes in balloon or stent-induced injury are not well understood, and mechanistic targeting of leukocyte recruitment or function is crude. We determined the temporal and spatial distribution of different leukocytes after balloon and stent-induced injury in primate iliac arteries. Based on these data, we targeted neutrophil and monocyte recruitment selectively after angioplasty or stent implantation and demonstrated that monocyte-specific blockade achieved via blockade of the MCP-1 receptor CCR2, was effective at reducing neointimal hyperplasia after stenting. In contrast, combined neutrophil and monocyte blockade achieved by targeting the leukocyte ␤ 2 -integrin ␤-subunit CD18 was required to reduce neointimal hyperplasia after balloon injury.

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