Target complicity in the confirmation and disconfirmation of erroneous perceiver expectations: immediate and longer-term implications

The authors explored the role of target self-presentational goals in the expectation confirmation process within the context of simulated employment interviews. As predicted, applicants encouraged to be deferential inadvertently succumbed to their interviewers' expectation; applicants encouraged to be challenging, to advance their own agenda, did not. The challenging-motivated applicants succeeded in disconfirming negative expectations by presenting favorable information about themselves even in the face of negatively constraining interviewer questions; other theoretically relevant behaviors were not supported as mediators. Of added interest, the self-fulfilling prophecies observed for the deference-motivated applicants carried over to a 2nd interview because of changes in applicant self-perceptions following the 1st interview.     

Perlecan binds to the beta-amyloid proteins (A beta) of Alzheimer's disease, accelerates A beta fibril formation, and maintains A beta fibril stability

Perlecan is a specific heparan sulfate proteoglycan that accumulates in the fibrillar beta-amyloid (A beta) deposits of Alzheimer's disease. Perlecan purified from the Engelbreth-Holm-Swarm tumor was used to define perlecan's interactions with A beta and its effects on A beta fibril formation. Using a solid-phase binding immunoassay, freshly solubilized full-length A beta peptides bound immobilized perlecan at two sites, representing both high-affinity [K(D) = approximately 5.8 x 10(-11) M for A beta (1-40); K(D) = approximately 6.5 x 10(-12) M for A beta (1-42)] and lower-affinity [K(D) = 3.5 x 10(-8) M for A beta (1-40); K(D) = 4.3 x 10(-8) M for A beta (1-42)] interactions. An increase in the binding capacity of A beta (1-40) to perlecan correlated with an increase in A beta amyloid fibril formation during a 1-week incubation period. The high-capacity binding of A beta (1-40) to perlecan was similarly observed using perlecan heparan sulfate glycosaminoglycans and was completely abolished by heparin, but not by chondroitin-4-sulfate. Using a thioflavin T fluorometry assay, perlecan accelerated the rate of A beta (1-40) amyloid fibril formation, causing a significant increase in A beta fibril assembly over a 2-week incubation period at 1 h (2.8-fold increase), 1 day (3.6-fold increase), and 3 days (2.8-fold increase) in comparison with A beta (1-40) alone. Perlecan also initially accelerated the formation of A beta (1-42) fibrils within 1 h and maintained significantly higher levels of A beta (1-42) thioflavin T fluorescence throughout a 2-week experimental period in comparison with A beta (1-42) alone, suggesting perlecan's ability to maintain amyloid fibril stability. Perlecan's effects on A beta (1-40) fibril formation and maintenance of A beta (1-42) fibril stability occurred in a dose-dependent manner and was also mediated primarily by perlecan's glycosaminoglycan chains. Perlecan was the most effective enhancer and accelerator of A beta fibril formation when compared directly with other amyloid plaque components, including apolipoprotein E, alpha1-antichymotrypsin, P component, C1q, and C3. This study, therefore, demonstrates that perlecan not only binds to the predominant isoforms of A beta, but also accelerates A beta fibril formation and stabilizes amyloid fibrils once formed, confirming pivotal roles for perlecan in the pathogenesis of A beta amyloidosis in Alzheimer's disease.     

Increase in serotonin-1A autoreceptors in the midbrain of suicide victims with major depression-postmortem evidence for decreased serotonin activity

It has been hypothesized that a deficit in serotonin may be a crucial determinant in the pathophysiology of major depression. Serotonin-1A receptors are located on serotonin cell bodies in the midbrain dorsal raphe (DR) nucleus, and the activation of these receptors inhibits the firing of serotonin neurons and diminishes the release of this neurotransmitter in the prefrontal cortex. Repeated treatment with some antidepressant medications desensitizes serotonin-1A receptors in the rat midbrain. The present study determined whether the binding of [3H]8-hydroxy-2-(di-n-propyl)aminotetralin (8-OH-DPAT), an agonist at serotonin-1A receptors, is altered in the midbrain of suicide victims with major depression. Radiolabeling of the serotonin-1A receptor in the DR varied significantly along the rostral-to-caudal extent of the human midbrain. The binding of [3H]8-OH-DPAT to serotonin-1A receptors was increased significantly in the midbrain DR of suicide victims with major depression as compared with psychiatrically normal control subjects. In suicide victims with major depression, the increase in the binding of [3H]8-OH-DPAT to serotonin-1A receptors was detected in the entire DR and specifically localized to the dorsal and ventrolateral subnuclei. Enhanced radioligand binding of an agonist to inhibitory serotonin-1A autoreceptors in the human DR provides pharmacological evidence to support the hypothesis of diminished activity of serotonin neurons in suicide victims with major depression.     

Acute and chronic effects of bilateral lung transplantation without cardiopulmonary bypass on the first transplanted lung

BACKGROUND: Bilateral lung transplantation (BLT) without cardiopulmonary bypass (CPB) may exacerbate reperfusion injury to the initially engrafted lung because of increases in pulmonary flow during implantation of the second graft. METHODS: In a retrospective review of 23 BLT patients, we hypothesized that BLT without CPB injures the first transplanted lung measured by acute and late graft dysfunction compared to the second transplanted lung. Of the 23 BLT, 19 underwent transplantation without CPB while 4 patients were placed on CPB secondary to hemodynamic instability. RESULTS: Acute graft function was assessed by radiographic scoring of lung quadrants (blinded radiologist; 0 = no infiltrate; 1 = infiltrate; maximum = 2 per lung) and by arterial/alveolar oxygen tension ratios (PaO2/ FiO2) ratios. Late graft function was evaluated by quantitative perfusion scan. Lung perfusion was graded as abnormal if less than 50% on the right or less than 45% on the left (Fisher's exact). Radiographic scores were not different between first and second implanted lungs at 1 and 24 hours, PaO2/FiO2 ratios at 1 and 24 hours were 273+/-26 and 312+/-23, respectively, and perfusion scans at 3 and 12 months revealed normal differential blood flow. CONCLUSIONS: These findings suggest no acute or chronic differences occur between the first or second transplanted lung completed without CPB.     

A role for Mac-1 (CDIIb/CD18) in immune complex-stimulated neutrophil function in vivo: Mac-1 deficiency abrogates sustained Fcgamma receptor-dependent neutrophil adhesion and complement-dependent proteinuria in acute glomerulonephritis

Mac-1 (alphambeta2), a leukocyte adhesion receptor, has been shown in vitro to functionally interact with Fcgamma receptors to facilitate immune complex (IC)-stimulated polymorphonuclear neutrophil (PMN) functions. To investigate the relevance of Mac-1-FcgammaR interactions in IC-mediated injury in vivo, we induced a model of Fc-dependent anti-glomerular basement membrane (GBM) nephritis in wild-type and Mac-1-deficient mice by the intravenous injection of anti-GBM antibody. The initial glomerular PMN accumulation was equivalent in Mac-1 null and wild-type mice, but thereafter increased in wild-type and decreased in mutant mice. The absence of Mac-1 interactions with obvious ligands, intercellular adhesion molecule 1 (ICAM-1), and C3 complement, is not responsible for the decrease in neutrophil accumulation in Mac-1- deficient mice since glomerular PMN accumulation in mice deficient in these ligands was comparable to those in wild-type mice. In vitro studies showed that spreading of Mac-1-null PMNs to IC-coated dishes was equivalent to that of wild-type PMNs at 5-12 min but was markedly reduced thereafter, and was associated with an inability of mutant neutrophils to redistribute filamentous actin. This suggests that in vivo, Mac-1 is not required for the initiation of Fc-mediated PMN recruitment but that Mac-1-FcgammaR interactions are required for filamentous actin reorganization leading to sustained PMN adhesion, and this represents the first demonstration of the relevance of Mac-1-FcgammaR interactions in vivo. PMN-dependent proteinuria, maximal in wild-type mice at 8 h, was absent in Mac-1 mutant mice at all time points. Complement C3-deficient mice also had significantly decreased proteinuria compared to wild-type mice. Since Mac-1 on PMNs is the principal ligand for ic3b, an absence of Mac-1 interaction with C3 probably contributed to the abrogation of proteinuria in Mac-1-null mice.     

Extension of recombinant human RANTES by the retention of the initiating methionine produces a potent antagonist

Extension of recombinant human RANTES by a single residue at the amino terminus is sufficient to produce a potent and selective antagonist. RANTES is a proinflammatory cytokine that promotes cell accumulation and activation in chronic inflammatory diseases. When mature RANTES was expressed heterologously in Escherichia coli, the amino-terminal initiating methionine was not removed by the endogenous amino peptidases. This methionylated protein was fully folded but completely inactive in RANTES bioassays of calcium mobilization and chemotaxis of the promonocytic cell line THP-1. However, when assayed as an antagonist of both RANTES and macrophage inflammatory polypeptide-1 alpha (MIP-1 alpha) in these assays, the methionylated RANTES (Met-RANTES) inhibited the actions of both chemokines. T cell chemotaxis was similarly inhibited. The antagonistic effect was selective since Met-RANTES had no effect on interleukin-8- or monocyte chemotractant protein-1-induced responses in these cells. Met-RANTES can compete with both [125I]RANTES and [125I]IMP-1 alpha binding to THP-1 cells or to stably transfected HEK cells recombinantly expressing their common receptor, CC-CKR-1. These data show that the integrity of the amino terminus of RANTES is crucial to receptor binding and cellular activation.