Testing the Interactivity Principle: Effects of Mediation, Propinquity, and Verbal and Nonverbal Modalities in Interpersonal Interaction

Early channel reliance research compared different modes of communication to assess relationships among nonverbal and verbal cues. Emerging communication technologies represent a new venue for gaining insights into the same relationships. In this article, the authors advance a principle of interactivity as a framework for decomposing some of those relationships and report an experiment in which physical proximity—whether actors are in the same place ("co-located") or interacting at a distance ("distributed")—and the availability of other nonverbal environmental, auditory, and visual information in distributed modes is varied. Results indicate that both proximity and availability of nonverbal cues affect communication processes, social judgments participants make about each other, and task performance. The authors discuss implications about gains and losses due to presence of nonverbal features.     

Studies on a stabilisation of ubisemiquinone by Escherichia coli quinol oxidase, cytochrome bo

The Escherichia coli quinol oxidase, cytochrome bo, is closely related to the cytochrome c oxidase, cytochrome aa3 in all aspects of its structure and function except for the replacement of the cytochrome-c-binding site and its attendant CuA prosthetic group with a quinone-binding site. The putative oxidation of quinol by ferrihaem (cytochrome b) at this site in sequential one-electron steps requires the stabilisation of semiquinone. We have observed, by electron paramagnetic resonance, the properties of a ubisemiquinone radical in appropriately poised samples of purified enzyme reconstituted with excess ubiquinone. The ubisemiquinone is highly stabilised with respect to free ubisemiquinone; significant free radical can be observed even at pH 7.0, while at pH 9.0 the stability constant is 5-10. The pH dependence of the stability constant indicates that the anionic form of the semiquinone predominates above pH 7.5. The two-electron couple has an Em7 of approximately 70 mV. Below pH 9, the pH dependence of the two-electron couple is -60mV/pH, indicative of a 2H+/2e- reaction. The line width of the EPR spectrum is approximately 0.9 mT, which is consistent with a ubisemiquinone anion. In comparison with other respiratory chain Q.- species that have been described, the relaxation rate in the presence of reduced haems appears comparable to magnetically isolated Q.- radicals. Partially resolved splittings of approximately 0.4 mT can be observed in the spectrum of Q.-bo (QH.bo).     

The microbiology of secretory otitis

The AA. realize a comparative study on the differences between the nasopharyngeal microbial flora of 50 children suffering a secretory otitis and other 40 children without middle ear disease. In nasopharyngeal cultures the pathogenic flora (Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis, Streptococcus beta hemoliticus group A, Staphilococcus aureus) amounted for 96 percent in children with secretory otitis, which figure was reduced to 80 percent in healthy infants (p < 0.05). Haemophilus influenzae was the most identified microorganism in a both nasopharyngeal and otic flora. We have found a significative association (p < 0.001) among nasopharyngeal and otic flora of each individual.     

Autocrine role for the endothelin-B receptor in the secretion of adrenomedullin

Adrenomedullin, originally discovered in human pheochromocytoma, is a vasodilating and natriuretic peptide of vascular endothelial and smooth muscle cell origin. Although endothelin-1 (ET-1) has been implicated as a vasoconstricting and growth-promoting peptide of endothelial origin, it may more importantly function as an autocrine factor and release vasodilatory substances such as nitric oxide by mechanisms linked to the endothelin-B (ETB) receptor subtype. The present study was designed to establish that the ETB receptor stimulates the secretion of adrenomedullin from cultured canine aortic endothelial cells. We first sought to determine the presence and production of adrenomedullin in canine aortic endothelial cells using immunohistochemistry and Northern blot analysis, which revealed that adrenomedullin immunoreactivity and adrenomedullin mRNA were present in canine aortic endothelial cells. Second, adrenomedullin was time-dependently secreted from canine aortic endothelial cells, with a secretion rate of 15.7+/-1.5 pg/10(5) cells per 24 hours. Furthermore, immunohistochemistry revealed the presence of the ETB receptor in canine aortic endothelial cells, and ETB receptor stimulation by sarafotoxin S6c increased adrenomedullin production and secretion from canine aortic endothelial cells. Such actions were blocked with the ETB receptor antagonist IRL-2500 but not with ETA receptor antagonist FR-139317. These studies are the first to report an additional autocrine role of the ETB receptor in the release of vasodilating and natriuretic peptide adrenomedullin, and they suggest another important vasoactive system regulated by the ET receptor subtype.     

Monocyte tissue factor-like activity in post myocardial infarction patients

It is widely recognized that thrombosis is the major event in the evolution of stable vascular disease to unstable ischaemic syndromes including myocardial infarction and stroke. The purpose of this case-control study was to establish clinical and laboratory data on the possible relationship between specific components of the haemostatic system and coronary heart disease. The procoagulant activity (PCA) of peripheral monocytes and polymorphonuclear neutrophils was assessed in 21 males who had suffered a myocardial infarction (MI) and in age-matched controls. In addition, total factor VII activity, fibrinogen, tissue factor pathway inhibitor (TFPI). D-dimers, tissue plasminogen activator (t-PA), plasminogen activator inhibitor (PAI-1), tumour necrosis factor-alpha (TNF-alpha) and full blood counts were measured. Post MI patients had significantly higher monocyte PCA, higher plasma concentrations of TFPI, fibrinogen, t-PA, T/P100 and also higher total white blood cell and neutrophil counts compared to age-matched controls. This elevated procoagulant state in post MI patients could further exacerbate the disease process and increase the risk of subsequent acute ischaemic events.     

gamma-Conotoxin-PnVIIA, a gamma-carboxyglutamate-containing peptide agonist of neuronal pacemaker cation currents

A novel gamma-carboxyglutamate-containing peptide, designated gamma-conotoxin-PnVIIA, is described from the venom of the molluscivorous snail Conus pennaceus. gamma PnVIIA, triggers depolarization and firing of action potential bursts in the caudodorsal neurons of Lymnaea. This effect is due to activation or enhancement of a slow inward cation current that may underly endogenous bursting activity of these neurons. The amino acid sequence of gamma PnVIIA was determined as DCTSWFGRCTVNS gamma CCSNSCDQTYC gamma-LYAFOS (where gamma is gamma-carboxyglutamate, O is trans-4-hydroxyproline), thus gamma PnVIIA belongs to the six cysteine four loop structural family of conotoxins, and is most homologous to the previously described excitatory conotoxin-TxVIIA. Interestingly, TxVIIA did not induce action potentials in Lymnaea caudodorsal neurons. gamma PnVIIA is the prototype of a new class of gamma-conotoxins that will provide tools for the study of voltage-gated pacemaker channels, which underly bursting processes in excitable systems.     

Receptor activity modifying proteins regulate the activity of a calcitonin gene-related peptide receptor in rabbit aortic endothelial cells

In Xenopus oocytes with an endogenous calcitonin gene-related peptide (CGRP) receptor, a receptor activity modifying protein (RAMP1) enhancing CGRP stimulated chloride currents of the cystic fibrosis transmembrane regulator was recently cloned [McLatchie, L.M. et al. (1998) Nature 393, 333-339]. Here, transient expression of RAMP1 in rabbit aortic endothelial cells (RAEC) brought about stimulation of cAMP accumulation by human (h) alphaCGRP with an EC50 of 0.41 nM. This was antagonized by a CGRP receptor antagonist alphaCGRP(8-37). Co-expression of RAMP3 together with RAMP1 reduced the maximal cAMP response to h alphaCGRP by 47% (P < 0.05). The cells also express RAMP2 encoding mRNA and an adrenomedullin (ADM) receptor coupled to stimulation of cAMP formation by hADM (EC50 0.18 nM). The latter was antagonized by an ADM receptor antagonist hADM(22-52). In conclusion, expression of a CGRP receptor in RAEC requires RAMP1. The same receptor presumably recognizes ADM making use of endogenous RAMP2. The results reveal competition between the different RAMPs in the regulation of CGRP/ADM receptor activity.     

Insights into Src kinase functions: structural comparisons

Recent structures of Src tyrosine kinases reveal complex mechanisms for regulation of enzymatic activity. The regulatory SH3 and SH2 domains bind to the back of the catalytic kinase domain via a linker region that joins the SH2 domain to the catalytic domain. Members of a subgroup of the Src kinase family show distinct features in this linker and in the loops that interact with it. Hydrophobicity of key residues in this region is important for intramolecular regulation. The kinases Abl, Btk and Csk seem to have the same molecular architecture as Src. Structural comparisons between serine/threonine and tyrosine kinases indicate a specific twisting mechanism involving the N- and C-terminal lobes of the catalytic domain. This motion could provide insights into the various mechanisms used to regulate kinase activity.     

Bibliometric index

The Institute of Scientific information has edited an index to evaluate the diffusion of scientific articles. It is based on the fact that the more an article is cited as a reference in other articles, the more it is considered to be important, and the higher the coefficient attributed to the journal in which it was originally published. The impact factor takes into account the average number of times which a journal is mentioned for recent articles published in a given year. This index is an attempt to quantify the notoriety of scientific journal for all scientific medical specialties.