GP130/OSMR is the only LIF/IL-6 family receptor complex to promote osteoblast differentiation of calvaria progenitors

Leukemia inhibitory factor (LIF) and its receptor (LIFR) are "twins" of Oncostatin M (OSM) and OSMR, respectively, likely having arisen through gene duplications. We compared their effects in a bone nodule-forming model of in vitro osteogenesis, rat calvaria (RC) cell cultures. Using a dominant-negative LIF mutant (hLIF-05), we showed that in RC cell cultures mouse OSM (mOSM) activates exclusively glycoprotein 130 (gp130)/OSMR. In treatments starting at early nodule formation stage, LIF, mOSM, IL-11, and IL-6 + sIL-6R inhibit bone nodule formation, that is, osteoprogenitor differentiation. Treatment with mOSM, and no other cytokine of the family, in early cultures (day 1-3 or 1-4) increases bone colony numbers. hLIF-05 also dose dependently stimulates bone nodule formation, confirming the inhibitory action of gp130/LIFR on osteogenesis. In pulse treatments at successive stages of bone nodule formation and maturation, LIF blocks osteocalcin (OCN) expression by differentiated osteoblasts, but has no effect on bonesialoprotein (BSP) expression. Mouse OSM inhibits OCN and BSP expression in preconfluent cultures with no or progressively reduced effects at later stages, reflecting the disruption of early nodules, possibly due to the strong apoptotic action of mOSM in RC cell cultures. In summary, LIFR and OSMR display differential effects on differentiation and phenotypic expression of osteogenic cells, most likely through different signal transduction pathways. In particular, gp130/OSMR is the only receptor complex of the family to stimulate osteoprogenitor differentiation in the RC cell culture model. © 2005 Wiley-Liss, Inc.

Direct inhibitory effects of an antisense oligodeoxynucleotide upon the volume-sensitive chloride current in rat osteoblast-like (ROS 17/2.8) cells

The effects of a 15-mer antisense c-myc phosphorothioate modified oligodeoxynucleotide (OdN) upon the volume-sensitive Cl- current in ROS 17/2.8 cells were investigated using the whole-cell configuration of the patch clamp technique. At 5 microM, the OdN reversibly inhibited the current in a voltage- and time-dependent fashion. This was evident from the reduction in the peak current as assessed at the termination of each voltage pulse and an acceleration of the time-dependent inactivation present at strongly depolarised potentials. The kinetic modifications induced by the OdN suggest it may act by blocking the pore of open channels when the cell membrane potential is depolarised.

Effects of arachidonic acid upon the volume-sensitive chloride current in rat osteoblast-like (ROS 17/2.8) cells.

1. The effects of arachidonic acid upon the volume-sensitive Cl- current present in cultured osteoblastic cells (ROS 17/2.8) was studied using the whole-cell patch-clamp technique. 2. Arachidonate produced two distinct phases of inhibition, a rapid phase occurring within 10-15 s of application preceding a slower phase that occurred 2 min after onset of arachidonate superfusion. Accompanying the slower inhibitory phase was an acceleration of the time-dependent inactivation exhibited by the current at strongly depolarized potentials (> + 50 mV). The half-maximal inhibitory concentrations (IC50) were 177 +/- 31 and 10 +/- 4 microM for the two phases respectively. 3. Arachidonate was still effective in the presence of inhibitors of cyclo-oxygenase (indomethacin, 10 microM), lipoxygenase (nordihydroguaretic acid, 10-100 microM) and cytochrome P450 (SKF525A, 100 microM; ethoxyresorufin, 10 microM; metyrapone, 500 microM; piperonyl butoxide, 500 microM; cimetidine, 1 mM). The effects of arachidonate could not be produced by another cis unsaturated fatty acid, oleic acid. 4. Measurements of cell volume showed that arachidonate effectively inhibited the regulatory volume decrease elicited by ROS 17/2.8 cells in response to a reduction in extracellular osmolarity. 5. It is concluded that the volume-sensitive Cl- conductance in ROS 17/2.8 cells is directly modulated by arachidonate and may represent a physiological mechanism by which volume regulation can be controlled in these cells.

Characterization of a volume-sensitive chloride current in rat osteoblast-like (ROS 17/2.8) cells

1. During osmotic swelling, cultured osteoblastic cells (ROS 17/2.8) exhibited activation of large amplitude Cl- currents in the whole-cell configuration of the patch-clamp technique. Effects of hypotonic shock on cell volume and membrane conductance were rapidly reversed on return to isotonic conditions. 2. Voltage command pulses in the range -80 to +50 mV produce instantaneous activation of Cl- currents. At potentials more positive than +50 mV the current exhibited time-dependent inactivation. The instantaneous current-voltage relationship was outwardly rectifying. 3. The anion permeability sequence of the induced current was SCN- (2.2) > I- (1.9) > Br- (1.5) > Cl- (1.0) > F- (0.8) > gluconate- (0.2). This corresponds to Eisenman's sequence I. 4. The volume-sensitive Cl- current was effectively inhibited by the Cl- channel blockers 4,4'-diisothiocyanatostilbene-2,2-disulphonic acid (DIDS) and 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB). Outward currents were more effectively suppressed by DIDS than inward currents. The concentrations for 50% inhibition (IC50) of outward and inward currents were 81 and 298 μM, respectively. NPPB was equally effective at inhibiting outward and inward currents (IC50 of 64 μM). The current was relatively insensitive to diphenylamine-2-carboxylate (DPC), 500 μM producing only 22.5 ± 4.0% inhibition. 5. Inhibitors of protein kinase A (H-89, 1 μM) and tyrosine kinase (tyrphostin A25, 200 μM) were without effect upon activation of Cl- currents in response to hypotonic shock. Under isotonic conditions, elevation of intracellular Ca2+ by ionomycin (1 μM) or activation of protein kinase C by 12-O-tetradecanoylphorbol 13-acetate (TPA, 0.1 μM) failed to evoke increases in basal Cl- conductance levels. 6. It is concluded that an outwardly rectifying Cl- conductance is activated upon osmotic swelling and may be involved in cell volume regulation of ROS 17/2.8 cells.

Within-country ethnic differences and product positioning:a comparison of the perceptions of two British sub-cultures

While cross-cultural consumer behaviour and its impact on marketing strategies has received considerable interest within the marketing literature, differences between ethnic groups within countries have received significantly less attention. This study examines the effect of within-country ethnic differences on brand positioning, using the UK automobile industry as a context. Both qualitative and quantitative research is used to identify the perceptions of two sub-cultural groups: British of Indian extraction, and Caucasian British. It was found that these two groups display appreciably different values, and also place different levels of importance on different product attributes when evaluating brands. Furthermore, the two groups exhibited different perceptions of the same set of brands. The results suggest that, to position brands effectively, marketers should take account of cultural diversity within countries as well as between them.

Terms of abuse as expression and reinforcement of cultures

In this study terms of abuse are investigated in 11 different cultures. Spontaneous verbal aggression is to a certain extent reminiscent of the values of a certain culture. Almost 3000 subjects from Spain, Germany, France, Italy, Croatia, Poland, Great Britain, USA, Norway, Greece, and The Netherlands were asked to write down terms of abuse that they would use given a certain stimulus situation, and in addition, to give their rating of the offensive character of those terms. A total set of 12,000 expressions was collected. The frequencies of the expressions were established, and the total list of expressions was reduced to 16 categories. Results point to some etic taboos, like sexuality and lack of intelligence. On the other hand clear differences across cultures were found, which cannot easily be explained by existing classifications of national cultures. Explanations are provided in terms of dimensions on which the 11 cultures differ.

Antimicrobial efficacy of chlorhexidine digluconate alone and in combination with eucalyptus oil, tea tree oil and thymol against planktonic and biofilm cultures of Staphylococcus epidermidis

Objectives Effective skin antisepsis and disinfection of medical devices are key factors in preventing many healthcare-acquired infections associated with skin microorganisms, particularly Staphylococcus epidermidis. The aim of this study was to investigate the antimicrobial efficacy of chlorhexidine digluconate (CHG), a widely used antiseptic in clinical practice, alone and in combination with tea tree oil (TTO), eucalyptus oil (EO) and thymol against planktonic and biofilm cultures of S. epidermidis. Methods Antimicrobial susceptibility assays against S. epidermidis in a suspension and in a biofilm mode of growth were performed with broth microdilution and ATP bioluminescence methods, respectively. Synergy of antimicrobial agents was evaluated with the chequerboard method. Results CHG exhibited antimicrobial activity against S. epidermidis in both suspension and biofilm (MIC 2–8 mg/L). Of the essential oils thymol exhibited the greatest antimicrobial efficacy (0.5–4 g/L) against S. epidermidis in suspension and biofilm followed by TTO (2–16 g/L) and EO (4–64 g/L). MICs of CHG and EO were reduced against S. epidermidis biofilm when in combination (MIC of 8 reduced to 0.25–1 mg/L and MIC of 32–64 reduced to 4 g/L for CHG and EO, respectively). Furthermore, the combination of EO with CHG demonstrated synergistic activity against S. epidermidis biofilm with a fractional inhibitory concentration index of <0.5. Conclusions The results from this study suggest that there may be a role for essential oils, in particular EO, for improved skin antisepsis when combined with CHG.

Empowerment effects across cultures

It is evident that empowerment is in widespread use as a management tool in international organisations. A comprehensive literature review identified that empowerment exists as two distinct constructs: relational empowerment and psychological empowerment. Building on this delineation, existing literature was used to develop a conceptual model of the antecedents and consequences of the two empowerment constructs. Furthermore, the impact of national culture was considered, resulting in a set of testable hypotheses concerning the cross-cultural differences in the relationships between empowerment and its antecedents and consequences. A quantitative study was undertaken to test the hypothesised conceptual model. Data were collected from India and the UK, via drop-off self-administered surveys from front-line employees of both an indigenous and multinational bank in the two cultures, achieving a total of 626 fully usable responses across the four samples. Rigorous scale development for all samples was undertaken and measurement invariance examined. Following this, the conceptual model was tested using latent variable path analysis. The results for the model were both encouraging and surprising. Similar results regarding the effects of relational empowerment and psychological empowerment were found across the two cultures. However, an examination of the antecedents to relational empowerment produced significantly different results across the cultures. Relational empowerment was found to have higher practical value as it had a significant positive effect on employee job satisfaction levels across both cultures.

The impact of national cultures and interpersonal factors on managerial communication

This study was undertaken for two primary purposes. The first was to discover whether or not two of the four cultural dimensions depicted by Hof-stede (1980), namely Power Distance and Uncertainty Avoidance, could be repeated using samples from seven organizations operating in three distinct cultural settings. The second was to assess the degree to which these dimensions affect superior-subordinate communication across the culturally-different groups. Also, the impact of the three interpersonal factors: Trust in Superior, Upward Influence and Mobility Aspirations was investigated cross-culturally. Participants were 291 managers from seven organizations; four Sudanese, two white British and an organization in Britain run by a group of British citizens of Pakistani extraction. It was hypothesized that the Power Distance and Uncertainty Avoidance of the three groups would replicate Hof-stede's. Specific implications of these dimensions for organizational communication and in particular for superior-subordinate communication were also hypothesized. Multiple regression analyses were performed with items of the two cultural dimensions and the three interpersonal factors (each in turn) forming the independent variables, while the organizational communication aspects formed the dependent variables. T-tests between means were also used to compare and contrast issues such as directionality of information flow across organizations operating in these settings. Work-related values of each of the three cultural groups provided support for Hofstede's model. However, only tentative support was given to the hypothesized relationships between the cultural dimensions and organizational communication. Similarly, weak associations were found between the three interpersonal factors and superior-subordinate communication behaviour. Some practical and theoretical implications are offered. An evaluation of the study and recommendation for further research are also given.

Antifoam addition to shake flask cultures of recombinant Pichia pastoris increases yield

Pichia pastoris is a widely-used host for recombinant protein production. Initial screening for both suitable clones and optimum culture conditions is typically carried out in multi-well plates. This is followed by up-scaling either to shake-flasks or continuously stirred tank bioreactors. A particular problem in these formats is foaming, which is commonly prevented by the addition of chemical antifoaming agents. Intriguingly, antifoams are often added without prior consideration of their effect on the yeast cells, the protein product or the influence on downstream processes such as protein purification. In this study we characterised, for the first time, the effects of five commonly-used antifoaming agents on the total amount of recombinant green fluorescent protein (GFP) secreted from shake-flask cultures of this industrially-relevant yeast.

Research cultures and the pragmatic functions of humor in academic research presentations:A corpus-assisted analysis

Based on a corpus of English, German, and Polish spoken academic discourse, this article analyzes the distribution and function of humor in academic research presentations. The corpus is the result of a European research cooperation project consisting of 300,000 tokens of spoken academic language, focusing on the genres research presentation, student presentation, and oral examination. The article investigates difference between the German and English research cultures as expressed in the genre of specialist research presentations, and the role of humor as a pragmatic device in their respective contexts. The data is analyzed according to the paradigms of corpus-assisted discourse studies (CADS). The findings show that humor is used in research presentations as an expression of discourse reflexivity. They also reveal a considerable difference in the quantitative distribution of humor in research presentations depending on the educational, linguistic, and cultural background of the presenters, thus confirming the notion of different research cultures. Such research cultures nurture distinct attitudes to genres of academic language: whereas in one of the cultures identified researchers conform with the constraints and structures of the genre, those working in another attempt to subvert them, for example by the application of humor. © 2012 Elsevier B.V.

Importance of syndecan-4 and syndecan -2 in osteoblast cell adhesion and survival mediated by a tissue transglutaminase-fibronectin complex

Tissue transglutaminase (TG2) has been identified as an important extracellular crosslinking enzyme involved in matrix turnover and in bone differentiation. Here we report a novel cell adhesion/survival mechanism in human osteoblasts (HOB) which requires association of FN bound TG2 with the cell surface heparan sulphates in a transamidase independent manner. This novel pathway not only enhances cell adhesion on FN but also mediates cell adhesion and survival in the presence of integrin competing RGD peptides. We investigate the involvement of cell surface receptors and their intracellular signalling molecules to further explore the pathway mediated by this novel TG-FN heterocomplex. We demonstrate by siRNA silencing the crucial importance of the cell surface heparan sulphate proteoglycans syndecan-2 and syndecan-4 in regulating the compensatory effect of TG-FN on osteoblast cell adhesion and actin cytoskeletal formation in the presence of RGD peptides. By use of immunoprecipitation and inhibitory peptides we show that syndecan-4 interacts with TG2 and demonstrate that syndecan-2 and the a5ß1 integrins, but not a4ß1 function as downstream modulators in this pathway. Using function blocking antibodies, we show activation of a5ß1 occurs by an inside out signalling mechanism involving activation and binding of protein kinase PKCa and phosphorylation of focal adhesion kinase (FAK) at Tyr861 and activation of ERK1/2.

Religious young adults recounting the past:narrating sexual and religious cultures in school

Schooling can be a pivotal time in young people’s formative experience when identities are negotiated and forged. However, contradictory dominant cultures can operate within the school context, making it very challenging for individuals to negotiate their religious and sexual identities within a sexualised and heteronormative space. This essay draws on interview data relating to 18- to 25-yearolds of diverse religious faiths in the UK, who recounted their secondary schooling experiences, and focuses on the formal and informal ways in which the school was constituted in relation to religion and sexuality.

Organisational cultures and management styles in four African countries:a cross-cultural study

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